10.7 Volume and Surface Area

3 min readjune 18, 2024

Geometric measurements are all about understanding shapes and their properties. From to , these formulas help us calculate the size and space of various 3D objects like prisms and cylinders.

But it's not just about math! These concepts have real-world applications too. We'll look at how to optimize packaging, design efficient containers, and solve practical problems using geometric measurements.

Geometric Measurements

Surface area and volume formulas

Top images from around the web for Surface area and volume formulas
Top images from around the web for Surface area and volume formulas
  • Surface area formulas for right prisms
    • General formula SA=2B+PhSA = 2B + Ph calculates surface area using the area of the (BB), of the base (PP), and (hh)
    • formula SA=2(lw+lh+wh)SA = 2(lw + lh + wh) uses length (ll), width (ww), and height (hh)
    • formula SA=bh+2ls+ls1+ls2SA = bh + 2ls + ls_1 + ls_2 uses base length (bb), height (hh), lateral length (ll), and side lengths of the triangular base (s,s1,s2s, s_1, s_2)
  • Surface area formula for right cylinders
    • SA=2πrh+2πr2SA = 2\pi rh + 2\pi r^2 calculates surface area using the (rr) and height (hh)
  • Volume formulas for right prisms
    • General formula V=BhV = Bh calculates volume using the area of the base (BB) and height (hh)
    • Rectangular formula [V = lwh](https://www.fiveableKeyTerm:V_=_lwh) uses length (ll), width (ww), and height (hh)
    • Triangular prism formula V=12bhlV = \frac{1}{2}bhl uses base length (bb), height (hh), and lateral length (ll)
  • Volume formula for right cylinders
    • V=πr2hV = \pi r^2h calculates volume using the radius (rr) and height (hh)

Real-world optimization applications

  • Maximizing volume given a fixed surface area
    • Determines the dimensions that result in the greatest volume while using a limited amount of material (fixed surface area)
    • Cylindrical can example finds the optimal height and radius to maximize the volume of the can given a fixed amount of material for the surface
  • Minimizing surface area given a fixed volume
    • Finds the dimensions that require the least amount of material (surface area) to contain a specific volume
    • Rectangular box example determines the length, width, and height that minimize the material needed to make a box with a fixed volume
  • Cost
    • Considers the cost of materials and the volume of goods to determine the most cost-effective dimensions for a container or package
    • Shipping container example finds the optimal size that balances material costs with the volume of goods being transported

2D vs 3D geometric measurements

  • (2D) objects
    • Flat shapes that have length and width but no depth (squares, rectangles, triangles, circles)
    • Perimeter measures the distance around the outside of the shape
    • Area measures the amount of space inside the shape
  • (3D) objects
    • Shapes that have length, width, and depth or height (cubes, prisms, cylinders, spheres)
    • Surface area measures the total area of all surfaces of the object
    • Volume measures the amount of space inside the object
  • Relationship between 2D and 3D
    • 2D shapes form the bases and faces of 3D objects
    • Rectangle (2D) can be the base of a rectangular prism (3D) and also forms the faces of the prism

Advanced 3D Shapes and Concepts

  • : A 3D shape with flat polygonal faces, straight edges, and vertices
  • shapes: 3D objects where the sides are not perpendicular to the base
  • : The portion of a solid (often a or pyramid) that lies between two parallel planes cutting the solid
  • : The distance from the apex to the base along the lateral surface in pyramids and cones

Key Terms to Review (33)

A = 4πr²: The formula A = 4πr² is used to calculate the surface area of a sphere, where A represents the surface area and r represents the radius. This equation highlights the relationship between a sphere's dimensions and its surface, emphasizing how changes in radius directly impact the total area that covers the sphere. Understanding this formula is crucial for applying geometric principles in various fields such as physics, engineering, and computer graphics.
Archimedes: Archimedes was an ancient Greek mathematician, physicist, engineer, inventor, and astronomer who is best known for his contributions to geometry, particularly in calculating the area and volume of various shapes. His work laid the groundwork for understanding surface area and volume formulas used for three-dimensional objects, influencing modern mathematics and science significantly.
Base: In mathematics, a base is a fundamental component that serves as the reference point for various operations, such as exponentiation or measurement in geometry. It indicates the number that is being multiplied by itself in exponentiation, the unit of measure in area and volume calculations, and the foundational side in geometric shapes like triangles. Understanding the concept of base is essential for grasping how numbers and shapes relate to one another in mathematical expressions and equations.
Cavalieri's principle: Cavalieri's principle states that if two solids have the same height and the same cross-sectional area at every level, then they have the same volume. This principle connects geometry and calculus, helping to establish relationships between different three-dimensional shapes and their dimensions, particularly when analyzing volume and surface area.
Cone: A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (typically circular) to a single point called the apex or vertex. This unique structure allows it to have distinct volume and surface area formulas, making it an important figure in various applications ranging from mathematics to real-world contexts.
Cross-section: A cross-section is a two-dimensional shape that is created when a three-dimensional object is sliced through a plane. This concept is essential for visualizing and calculating the volume and surface area of solids, as it allows for a clearer understanding of the internal structure and dimensions of an object when viewed from different angles.
Cube: A cube is a three-dimensional geometric figure with six equal square faces, twelve equal edges, and eight vertices. This shape is significant in understanding volume and surface area because it represents a fundamental unit of space in three dimensions, making it easier to calculate the amount of space it occupies and the area of its outer surfaces.
Cubic meters: Cubic meters are a unit of volume measurement that represents the amount of space an object occupies in three-dimensional space. One cubic meter is equivalent to the volume of a cube with each side measuring one meter. This metric unit is essential in various applications such as construction, shipping, and scientific research, allowing for precise calculations related to volume and capacity.
Cylinder: A cylinder is a three-dimensional geometric shape consisting of two parallel circular bases connected by a curved surface at a fixed distance from the center of the circles. This shape is commonly encountered in various practical applications, such as in the design of containers and structures. The measurements of a cylinder, including its volume and surface area, are crucial for understanding its capacity and the material needed for construction.
Frustum: A frustum is the portion of a solid, typically a cone or a pyramid, that lies between two parallel planes cutting through the solid. It has a top base and a bottom base that are parallel to each other and are typically different in size, creating a truncated shape. Understanding frustums is essential for calculating volumes and surface areas of these solids, particularly in real-world applications like design and architecture.
Geometric solids: Geometric solids are three-dimensional shapes with length, width, and height. They include objects like cubes, spheres, cylinders, and pyramids.
Height: Height refers to the measurement of an object from its base to its topmost point. This dimension is crucial in various geometric contexts, influencing calculations related to area, volume, and surface area. Understanding height is essential for determining the size and capacity of three-dimensional shapes, as well as for analyzing hierarchical structures in data representation.
Lateral area: Lateral area refers to the surface area of the sides of a three-dimensional shape, excluding its bases. It is a crucial concept when calculating the total surface area of solids, as it helps in understanding how much area the sides of a shape cover without accounting for the top and bottom surfaces. Lateral area plays a significant role in various applications, including material estimation and packaging design.
Oblique: In geometry, an oblique shape is one that is not perpendicular or parallel to the axes, meaning it has a slant or tilt. This property is significant when calculating the volume and surface area of three-dimensional shapes, as oblique forms can lead to different formulas compared to their regular counterparts, such as prisms or pyramids.
Optimization: Optimization is the process of finding the best solution or outcome from a set of possible choices, often subject to certain constraints. It plays a vital role in decision-making where the goal is to maximize or minimize a specific function, whether it be cost, time, efficiency, or resources. This concept is applied in various fields to analyze and improve systems, ensuring that limited resources are used effectively.
Perimeter: Perimeter is the total distance around the boundary of a two-dimensional shape. It plays a crucial role in various geometric calculations, linking to the area, volume, and surface area of shapes by providing a foundational measure of length that helps in understanding the dimensions and characteristics of polygons and circles.
Pi: Pi is a mathematical constant representing the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. This irrational number is crucial in understanding properties of circles and is widely used in various fields including geometry, physics, and engineering.
Polyhedron: A polyhedron is a three-dimensional geometric shape with flat polygonal faces, straight edges, and vertices. These shapes can be classified into various types based on the number and arrangement of their faces, such as prisms, pyramids, and more. The volume and surface area of polyhedra can be calculated using specific formulas, which are essential for understanding their properties in geometry.
Prism: A prism is a three-dimensional geometric shape that has two parallel, congruent bases connected by rectangular faces. Prisms can take various forms depending on the shape of their bases, such as triangular or rectangular, and they play a crucial role in calculating both volume and surface area in geometry.
Radius: The radius is the distance from the center of a circle or sphere to any point on its boundary. It is a crucial concept that helps define the size and shape of various geometric figures, influencing their perimeter, circumference, area, volume, and surface area.
Rectangular prism: A rectangular prism is a three-dimensional geometric shape that has six rectangular faces, with opposite faces being equal in area. This shape can also be referred to as a cuboid, and it plays a significant role in calculating volume and surface area, making it essential for understanding spatial measurements.
Right cylinder: A right cylinder is a 3-dimensional geometric shape with two parallel circular bases connected by a curved surface, and the axis (line segment joining the centers of the bases) is perpendicular to the bases. It resembles a soup can or a drum.
Right Cylinder: A right cylinder is a three-dimensional geometric shape with two parallel circular bases connected by a curved surface at a fixed distance from the center of the circles. The axis of the cylinder is perpendicular to the bases, ensuring that the sides are straight and parallel, which is essential for calculating both volume and surface area. Understanding the properties of right cylinders is crucial in various applications, including engineering and architecture.
Right prism: A right prism is a three-dimensional geometric shape that has two parallel, congruent bases connected by rectangular lateral faces. This shape allows for straightforward calculations of both volume and surface area due to its uniform cross-section along the height. The simplicity of a right prism’s structure makes it essential for understanding three-dimensional space and geometry.
Slant Height: Slant height is the distance measured along the lateral surface of a three-dimensional geometric shape, particularly cones and pyramids, from the base to the apex. This measurement is essential for calculating both the surface area and volume of these shapes, as it allows for a precise understanding of their dimensions and the geometric relationships within them.
Sphere: A sphere is a perfectly symmetrical three-dimensional shape where every point on its surface is equidistant from its center. This geometric figure is fundamental in understanding volume and surface area, as it helps us calculate the space contained within it and the area that covers its outer surface. The sphere's unique properties make it significant in various mathematical applications, including physics and engineering.
Square feet: Square feet is a unit of area measurement that represents the size of a two-dimensional space, specifically the area of a square with each side measuring one foot in length. It’s commonly used to quantify space in real estate, architecture, and construction, making it essential for understanding how much surface area is available for various uses. This term connects closely with concepts of volume and surface area since knowing the area can help determine how much material is needed for surfaces and how structures will be designed.
Surface area: Surface area is the total area that the surface of a three-dimensional object occupies. It plays a crucial role in understanding properties like volume, material use, and heat transfer. Knowing how to calculate surface area helps in practical applications, such as determining the amount of paint needed for a wall or the capacity of containers.
Three-dimensional: Three-dimensional refers to objects or spaces that have height, width, and depth, allowing for the representation of volume. This concept is essential when discussing figures like cubes, spheres, and pyramids, which occupy space and can be measured in terms of volume and surface area. Understanding three-dimensionality is crucial for calculating how much space an object takes up and the area that its surface covers.
Triangular prism: A triangular prism is a three-dimensional geometric shape with two parallel triangular bases connected by three rectangular faces. This solid shape has volume and surface area properties that can be calculated using specific formulas, making it an important figure in geometry and spatial reasoning.
Two-dimensional: Two-dimensional refers to a geometric space that has two dimensions, typically defined as length and width. This concept is foundational in understanding shapes and figures that exist in a flat plane, allowing for the measurement of area and the representation of objects visually. Two-dimensional figures are essential for calculating surface areas and play a critical role in various applications, including design, engineering, and art.
V = lwh: The equation V = lwh represents the formula for calculating the volume of a rectangular prism, where V is the volume, l is the length, w is the width, and h is the height. This formula helps to quantify the space occupied by three-dimensional objects, allowing for practical applications in various fields such as architecture, engineering, and everyday problem solving. Understanding this formula also leads to insights about related concepts like surface area and how to manipulate dimensions to achieve desired volume measurements.
Volume: Volume refers to the amount of three-dimensional space occupied by a substance or object, typically measured in cubic units. Understanding volume is essential for various applications, such as calculating the capacity of containers, determining the amount of material needed for construction, or analyzing physical properties in science and engineering. It connects closely with area, as the base area of a solid and its height determine its overall volume.
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