Atriangular prism has a surface area of 550 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.

Triangular prism looks like the attachment, very handy

legnth=a=15
side=b=5
width=c=c
height=h=10

as attahcment

SA=h(a+b+c)
SA=10(15+5+c)
550=SA
550=10(15+5+c)
divide both sides by 10
55=15+5+c
55=20+c
minus 20 both sides
35=c

width=35 feet