Answer:
The length of the container is 
Step-by-step explanation:
we know that
The surface area of a triangular prism (a mailing container) is equal to

where
B is the area of the triangular base
P is the perimeter of the triangular base
L is the length of the container
step 1
Find the area of the base B

step 2
Find the perimeter of the base P

step 3
Find the length L of the container
we have



substitute and solve for L

![L=[87.4-2(1.7)]/(6)](https://tex.z-dn.net/?f=L%3D%5B87.4-2%281.7%29%5D%2F%286%29)
