Question

A triangular prism has a surface area of 350 square feet, a length of 15 feet, a height of 10 feet, and a side of 5 feet. Find the width of the triangular prism
Please help!

Answer 1

Let's see...

S. A = 350
l = 15 ft
h = 10
s = 5 ft
w =?



Let's flatten the prism:


We have two triangles:

The area for a triangle is (w x h) / 2
Since there are two triangles it should be 2[ (w x h) / 2 ] = w x h

We have three rectangles:
The area for a rectangle is l x w
Since there are 3 triangles, it should be 3 (l x w)

So the surface area is: 3 (l x w) + (w x h)

S.A = 3 (l x w) + (w x h)

Solve the equation in terms of "w"
S.A= 3 l + 3w + wh
S.A = 3l + w( 3+h)
S.A - 3l = w (3+h)

w = (S.A - 3l ) / (3+h)

Substitute your given values in the formula and you're done :)