Marisol is painting on a piece of canvas that has and area of 180 square inches. The length of the painting is 1 1/4 times the width. What are the dimensions of the painting?

Formula for the rectangle area is a * b, In this case we know that:

a * b = 180

a (width) = unknown

b (length) = 1 1/4a

We can write it down as:

a * 1 1/4 * a = 180

a² * 1 1/4 = 180 / : 1 1/4 (both sides)

a² = 144 / square root (both sides)

a = 12

Doublecheck:

a = 12

b = 1 1/4 * 12 = 15

a * b = 12 * 15 = 180 (so it's correct)

Answer: The dimensions of the painting are 12 x 15 inches.