An artificial lake is in the shape of a rectangle and has same 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?

You are given an artificial lakes’ shape of a rectangle having an area of 9/20 square mile and width of 1/5 length of the lake. You are required to look for the dimensions of the lake. The area of a rectangle is length times width. So,  
Area = length * width  
Since width = 1/5 length  
Area = length * 1/5 length  
Area is 9/20 square mile,  
9/20 square mile = 1/5 * square length
Square length = 9/4 square mile
Length = 3/2 mile