Question

I asked this yesterday and didn't get a response. I know it is difficult since you can't see the picture on my homework. Can you tell me if I started correctly and used the correct formula for surface area of a triangular prism?

Is there a way to post a pic to help explain this?
(I will try and explain the triangular prism. it has a 90 angle. the long end of the triangle is 13.5 in. One side is 10 in and the other side of the triangle is 9 in. the side coming down from the triangle making the prisms length is 9 in.

I need help with this problem.
It asks what is the surface area of the prism?
The formula I used was
SA=W(A)+L(W)+L(H)+L(S)
SA=9(10)+9(9)+9(10)+9(13.5)
SA=90+81+90+121.50
SA=382.5 in^2

I asked two of my friends to help and we all had different answers, so I would appreciate any help. I hope you can see the pic or else maybe you can even tell me if the formula I used was correct.
Thank you so much for your help

Answer 1

First of all I checked for the right-angle , and
10^2 + 9^2 = appr 13.5^2

Look at your diagram:
Your surface area would consist of the 3 rectangles plus the two equal triangles.
the height of the rectangles is 9 inches,

Area of rectangles = 9x10 + 9x9 + 9x13.5
= 292.5
area of the two identical triangles
area of triangle = (1/2)base x height
= 2( (1/2)(10)(9))
= 90

total area = 292.5 + 90
= 382.5

You had that!

Since I can't see your diagram, I don't know what all those variables in
SA=W(A)+L(W)+L(H)+L(S)
really are. Nevertheless, your calculations match mine.

Answer 2

thank you so much!