A ratio is a relationship between two quantities, sizes, or amounts. For example, 4 quarters is equal to 1 dollar, represented as a 4:1 ratio. Similarly, 25 pennies is equal to 1 quarter, or a 25:1 ratio. When drawing objects using ratios, the shape cannot be changed - a 1:2 ratio carrot drawing cannot simply be cut in half, and both the length and height must be proportionally scaled when drawing the perimeter of a house.