Question

The length of a rectangle is two more than its width. Find the perimeter of this rectangle if its area is 15 ft.²

Answer 1

Perimeter = 16ft

Explanation:

Let the width(w) of the rectangle be x ft

The length(l) of the rectangle will be (x + 2) ft

Area of the rectangle is 15ft²

Area of a rectangle = l × w

(x + 2)x = 15

x² + 2x - 15 = 0

Applying the quadratic formula;

x = (-b ±
`√(b^2 - 4ac)`) ÷ 2a

x = (-2 ±
`√(4 - -60)`) ÷ 2

x = 3 or -5

Since the width can't be negative, we take 3ft to be the value of our width

The length is therefore 3ft + 2ft = 5ft

Perimeter(p) = 2l + 2w

p = 2(5) + 2(3) = 16ft