The height of a triangle is three inches less than the lenght of the base of the triangle. The area of the triangle is 90 in.2. Find the lenght of the triangle.

Question

anonymous · Answer

H = B - 3         1st sentence

Area of Triangle is  1/2 BH

Substitute in for H from the first sentence.

90 = 1/2 B (B - 3)     multiply both side by 2
180 = B(B - 3)
180 = B^2 - 3B      make it = to 0
0 = B^2 - 3B - 180     Factor
0 = (B - 15)(B + 12)
B = 15 or B = -12    You don't use the -12 because that can't be the Base length

B = 15
H = 15 - 3 = 12