Question

The length of a rectangle is 1 m less than double the width, and the area of the rectangle is 21 m^2. Find the dimensions of the rectangle.

Answer 1

Remember that

The area of a rectangle is equal to

A=L*W

In this problem

A=21 m2 ----> given

L=2W-1

substitute the given values in the formula of Area

21=(2W-1)*W

solve for W

21=2W^2-W

2W^2-W-21=0

Solve the quadratic equation

using a graphing tool

The value of W=3.5 m

Find out the value of L

L=2(3.5)-1

L=6 m

therefore

The dimensions are 6 m x 3.5 m