Answer:
12 inches
Step-by-step explanation:
Let b represent the base
h represents the height
area of the parallelogram = base * height = 216 square inches
From the question'
b = 18 + 3h
Slot in the value of b
216 = (18 + 3h) * h
expand
216 = 18h + 3h^2
subtract 216 from both sides
0 = 18h + 3h^2 - 216
rearrange
3h^2 + 18h - 216 = 0
divide through by 3
h^2 + 6h - 72 = 0
Now, lets solve!
h^2 + 6h - 12h - 72 = 0
h( h + 6 ) - 12(h + 6) = 0
(h - 12) (h + 6) = 0
h - 12 = 0
h = 12
and
h + 6 = 0
h = - 6
Taking the positive value of h
Hence, the height is 12 inches
Lets check
when h = 12 inches
Area of the parallelogram = 18* 12 = 216 square inches .... correct
when h = -6inches
A = 18 * -6 ≠ 216 square inches
So height is 12 inches
