Maths
posted by Florence .
If the base side of a triangle is (x+4) and the height is (x+1), what is x if the area is 20cm3?
Please demonstrate how you reached the answer. Thanks.

Area of a triangle = (1/2) (base)(height)
20 = (1/2)(x+4)(x+1)
40 = x^2 + 5x + 4
x^2 + 5x  36 = 0
(x+9)(x4) = 0
x = 4 or x = 9, the latter is silly in this context.
check:
if x=4, base is 8 and height is 5
what is (1/2)(8)(5) ?