The height of a triangle is 9 m less than its base. The area of the triangle is 56 m2. Find the length of the base.

Let the base be b.

The height is b - 9.

Area of triangle = 1/2 x base x height

56 m² = 1/2 x b x (b - 9)

56 = - 1/2b (b - 9)

112 = b² - 9b

b² - 9b - 112 = 0

(b + 7) (b - 16) = 0

b = - 7 (rejected, b cannot be negative) or b = 16

Answer: The base is 16 m