Surface area of roof

[swalker]

My new shop/garage will be 28'X42' (12' of long side will be a garage).

The roof slope will be 5/12.

How do I figure the area of the roof?

Thanks

Jim

[DerbyDad03]

[Gordon Shumway]

I bet you wish you paid closer attention in geometry class in high skool.

[DerbyDad03]

I forgot to mention that you need to add in the eaves and other overhangs. It's not just about the square footage of the building.

[swalker]

Well I did pay attention in class and found geometry to be fun and made a good grade.

I tried to solve this by using a^2 = (B^2)+(C^2) to find the long leg. The answer didn't seem right so I am looking to check it.

From the calculator above I made a mistake. Some where. Thanks for the calculator.

One thing I noted about geometry was that guys good at the pool table weren't necessarily good at geometry.

Jim

[swalker]

Yeah, I got that figured in.

[Leon]

That will depend on how the roof is built. One plane sloping from one side to other other will be less than a hip design. If you have gables on one or both ends that will change a little too.

[Greg Guarino]

5/12 is a particularly convenient slope actually. It's one of the famous Pythagorean Triples. Sides of 5, 12 and 13 make a right triangle. So if your horizontal and vertical measurements were actually 12 and 5, the "hypotenuse" length would be 13. If it's something else, just multiply the horizontal measurement by 13/12.

Your equation should work. Use the numbers above as an example 13^2 (169) = 5^2 (25) + 12^2 (144)

I wonder if you added up the squares of the two legs but forgot to take the square root of the result.

5

[dadiOH]

a2 + b2 = c2 ("2" = squared). Don't forget the overhang.

[Ed Pawlowski]

I knew that in high school when I had a 98 average in geometry. Fifty three years later, not so much. I wonder if I forgot anything else. Nah.

[Greg Guarino]

Hey, you remembered your grade, at least.

The most famous Pythagorean Triple is 3-4-5, reportedly used by the Ancient Egyptians to lay out accurate right-angle corners.

[Keith Nuttle]

Probably did not forget it, but replaced it with other important infromation like your social security number and the names of all of you doctors

[Puckdropper]

Ed Pawlowski wrote in news:- [e-mail]:

Happens to all of us. I used to be familiar with Calculus, but after college never calculated a derivative other than to show off. Now I'm filling the space with more important things... Like how to properly hit a softball. Let me tell you it's not about swinging your arms. Your entire body is involved.

Puckdropper

[DerbyDad03]

I've forgotten more stuff than most people know. At least I think I have...I don't really remember.

[Scott Lurndal]

Don't forget that Pythagorus requires a right triangle.

Take the triangle formed by the roof (22.5/22.5/135 degrees), bisect into two right-triangles, then use trig to calculate the hypotenuse length, since you know the length of the adjacent side (1/2 the length of the long side of the original triangle - the long side is opposite the 135 degree angle).

cos(90) = adjacent/hypotenuse

hypotenuse = cos(90)/adjacent

area = 2 x (hypotenuse x length of roof).

qed.

[krw]

Through all the (4) years of calculus we had to take, the instructors always said that we'd probably never use the skills again after graduation but that I should know how to use integration tables. Unfortunately, they never taught how to use them. I never really needed them, either but at times it would have been good to know.

[Swingman]

Simple ... model it in SketchUp, select the face, and right click the context menu for "area/selection".

;)

[Sonny]

dadiOH, check out these keyboard shortcuts:

Sonny

[russellseaton1]

Shooting pool ain't just about geometry. Left spin, right spin, back spin, over the top spin, force of the shot, hard kiss, soft kiss, it all adds up to making the ball go everywhere but in the pocket. Doubt old Pythagoras ever shot a game of pool in his life.

[graham]

Surely the area is bxcx13/12 Graham