An artificial lake is in the shape of a rectangle and has an area of 9/20 square mile. The width of the lake is 1/5 the length of the lake. What are the dimensions of the lake?

The area is width times length, so you'd divide the area by the width. This is 9/20 divided by 1/5. When dividing fractions, you flip the second number then divide straight across. This would be 9/20 x 5/1. You'd get 45/20, or in mixed number form, 2 and 1/4.