Answer:
252 inches
Step-by-step explanation:
Step 1:finding the area of triangle
b*h*1/2=3*4*1/2 but since there are two right angles in a triangular prism because of the two sides then its just 3*4 which is 12.
Step 2:finding the perimeter of the right angle
so 3,4 and 5 are known to be part of the right angle sp that means 3+4+5=12
Step 3:multiplying the height and perimeter of the triangular prism
20*12=240
Step 4;(A.K.A the final step)Adding the remaining numbers together.
240+12=252 inches