Mary needs to buy [tex]455~m^3[/tex] spray foam.
The correct answer is an option (B)
"Volume = base area × length,
where, Base area = area of triangle
Length = length(or height) of the triangular prism"
For given question,
Mary wants to get spray foam insulation in her attic space.
To find the amount of spray foam she needs to buy, we need to find the volume of the given triangular prism.
First we find the base area of the given triangular prism.
For a triangular base,
base = 7 m and height = 10 m
Using the formula of the area of the triangle,
[tex]A=\frac{1}{2}\times 7\times 10\\\\ A=7\times 5\\\\A=35~sq.m.[/tex]
Now, we find the volume of the triangular prism.
[tex]V=A\times l\\\\V=35\times 13\\\\V=455~m^3[/tex]
Therefore, she needs to buy [tex]455~m^3[/tex] spray foam.
The correct answer is an option (B)
Learn more about the volume of triangular prism here:
https://brainly.com/question/17004095
#SPJ2