Please please please help me

Answer:
b) 300in^2
Step-by-step explanation:
area of triangle = base x heigth / 2
10 . x 10 / 2 = 100/2 =50
surface area of one face is 50
there 4 sides so 50 x 4 = 200
and the bottom is length x width = 10 x 10 = 100
100 + 200 = 300