Question

In a rectangle, the length is 7 m less than three times the width and the area is 111 m. Approximate the dimensions to the nearest tenth of a meter.

Answer 1

The dimensions are 7.4m by 15.1 m (to the nearest tenth).

Explanation:

Area = length * width

If the width = x then the length = 3x - 7 so

Area x(3x - 7) = 111

3x^2 - 7x - 111 = 0

Using the quadratic formula:

x = [ -(-7) +/- √((-7)^2 - 4*3*-111)] / (2*3)

x = 7.36, -5.03.

The width must be positive s it is 7.36 m.

The length = 3(7.36) - 7

= 15.08 m.