Question 600854
The height of a triangle is 10 inches less than the three times the base. the area is 156 square inches. what is the base of the triangle?
.
Let b = base
then
3b-10 = height
.
area = (1/2)base*height
156 = (1/2)b(3b-10)
312 = b(3b-10)
312 = 3b^2-10b
0 = 3b^2-10b-312
solve using the quadratic formula to get:
x = {12, -8.67}
throw out the negative solution leaving
x = 12 inches
.
details of quadratic formula follows:
*[invoke quadratic "x", 3, -10, -312 ]