The altitude of a triangle is 6 cm greater than its base. if its area is 108 cm, find its base

Area of the triangle = (1/2) * base*height

base = x

height = altitude = x+6

Area of the triangle = (1/2) * x * (x+6) = 108

(1/2) * x * (x+6) = 108

x²+6x-216 = 0

(x+18) (x-12) = 0

x=-18, or x=12

We can use only positive value, so x=12.

Base = 12 cm.