Apply Area and Pythagorean Theorem to a prism

[Kirito123]

Homework Statement

Homework Equations

Formula for Area of a retangle : A = L x W
Pythagorean theorem: A² + b² = c²

The Attempt at a Solution

So I am pretty sure I did it correct but I just want to be 100% certain I will get this right, By the way its a picture cause I found it easier to just snip it then copy paste.

Thank you in advance for your help

 

[fresh_42]

Looks ok, as long as we disregard the fact that an area isn't measured in cubic feet and the "entire roof" is not 240 sqft. Calculation A, text D .

 

[haruspex]

He will not need approximately 15; he will need to buy exactly 15. It would not be possible to buy 0.54 of a bundle.

 

[Kirito123]

@har your right just noticed that and thanks you

@fresh thanks you to :)