Answer:
Remember that a triangle's area is bh/2, where
b = base
h = height
So. You start with a triangle of base b and height h, add 2 to the height, and get a triangle of area 82.5.
b(h+2)/2 = 82.5
b(h+2) = 165
What you want to do from here is test the b and h from the choices given, and figure out which b and h satisfy this.
(a) If b=13 and h=15, b(h+2) = 221 nope.
(b) If b=9 and h=11, b(h+2) = 117 nope.
(c) If b=11 and h=13, b(h+2) = 165 that's it!
Step-by-step explanation:
