# Roofing Problem

#### stephanie953

##### New member
Hey everyone. I am working on a computer science project that requires a equation for a roof. This is what my teacher has down and I don't think it is correct:

(house height)squared + (house width/2)squared = roof width
then roof width * house length = roof area

Does anyone know the correct formula or if this one is correct?

*Also if any one has any idea please post it. I need it for tomorrow.* Thanks

#### arthur ohlsten

##### Full Member
There appers to be something wrong with the equation of roof width.

If the home height is in feet, and the width is in feet, then the left side of the first equation is feet squared.; or the dimensions of roof width is in feet squared.

The width of the roof should be in feet not feet squared. The equation is in error

The second equation, [roof area = width times length] is correct for a flat roof.

Arthur

#### TchrWill

##### Full Member
I am working on a computer science project that requires a equation for a roof. This is what my teacher has down and I don't think it is correct:

(house height)squared + (house width/2)squared = roof width
then roof width * house length = roof area
Let Hh = the height of the rectangular house
Let Wh == the width of the rectangular house
Let Lh = the length of the rectangular house.
Let Hr = the height of the roof above the house height
Let Lr = the length of the rectangular roof = Lh
Let Wr = the width of each half of the rectangular roof.

Then, Wr = sqrt(Hr^2 + (Wh/2)^2

The area of the roof is then equal to 2(Wr((Lr).

If the height of the house is intended to be the height to the peak of the roof, then Hr = the height of the roof peak above the ground and Hh = the height of the rectangular house.

Then, Wr = sqrt[(Hr - Hh)^2 + (Wh/2)^2] and the roof area becomes
Ar = 2[sqrt(Hr - Hh)^2 + (Wh/2)^2]Lr

#### Denis

##### Senior Member
stephanie953 said:
This is what my teacher has down and I don't think it is correct:
(house height)squared + (house width/2)squared = roof width, then roof width * house length = roof area
Your teacher is obviously not a former roofer!