7. A mailer for posters is a triangular prism as shown. Find the surface area of the mailer. (Example 3) 4.7 in. 18 in. 4.7 in. M. lohn Sininh 1234 Anysvert Anytown, 4 in. 5 in.​

279.2 squared inches

Step-by-step explanation:

first find the base of the triangular prism which is  18*5=90.

then multiply 18*4.7 to get 84.6 then multiply that by 2 to get 169.2

then find the area of the triangles which is 4*5= 20 then add it all up which is equal to 279.2 ( 90 + 20) + 169.2= 279.2

Hope this was helpful :)