SOLUTION: The base of a triangle is 2cm more than the height. The base is increased by 4cm while the height is the same. The new area is 56cm. Whats the original area?

Algebra ->  Formulas -> SOLUTION: The base of a triangle is 2cm more than the height. The base is increased by 4cm while the height is the same. The new area is 56cm. Whats the original area?       Log On


   

Question 848321: The base of a triangle is 2cm more than the height. The base is increased by 4cm while the height is the same. The new area is 56cm. Whats the original area?

Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
b = h + 2
b-2 = h
After change, our base is b+4
A = (1/2) * b * h
56 = (1/2)*(b+4)*(b-2)
56 = (1/2)(b^2+2b-8)
112 = b^2 +2b - 8
b^2 +2b -120 = 0
(b-10)(b+12) = 0
b = 10 [ignore b= -12]
This means h = 8
original area = 1/2 *(10)*(8) = highlight%2840%29 cm^2