Ratio:A ratio is a comparison of two or more quantities, usually expressed as a fraction or a colon.
Proportion:A proportion is a statement of equality between two ratios, where the relationship between the quantities in one ratio is the same as the relationship in the other ratio.
Cross-Multiplication: Cross-multiplication is a method used to determine if two ratios are equivalent by multiplying the numerator of one ratio with the denominator of the other ratio, and vice versa.