Geometry: Solve for the Rectangle's height.

Question

The area of a rectangle is 36 cm2 . The height is three less than three times the base. What is the height?

Answer 1

H = 3B -3

A = BH, i.e. 36 = B(3B-3)

3B² - 3B - 36 = 0

Divide by 3 to get an expression which factors easily, giving the correct answer for B and an extraneous root.

Use the value of B to get H.