Find the area. Post up your answers.
https://lh3.googleusercontent.com/NV...=w1528-h956-no
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Find the area. Post up your answers.
https://lh3.googleusercontent.com/NV...=w1528-h956-no
Are you posting up your homework because you're too lazy to do it?
No, I already did it, but then I started to question whether I had enough information to do it correctly or not.
Also, without knowing the roof pitch, it's impossible to tell the sq footage of roof.
$4700 in roofing materials + labor . That doesn't include decking. Don't forget gutters & down spouts. Which will get trashed by the tear off crew. Throwing another $4200 in materials.
This is a roof with a slope, so you can't just turn this into two rectangles of 34'4 x 23'5 and 13'7 x 33'4.
42
It shouldn't matter since all the measurements were taken on the surface of each "shape." You're looking at the actual measurements, so I guess the eaves would be in scale with the ridges, and the hips in scale with the valleys. On this roof anyway, where everything is the same slope.Quote:
Originally Posted by HoneyBadger
But if the roof were flat, the area would be 1001-ish sq units (sq ft... I assume) Take the bigger box (40'8"x 37') and subtract the two smaller boxes (23'5" x 6'4" and 7'6" x 13'7")
Quote:
Originally Posted by HoneyBadger
Exactly. Because it has slope, there is a third measurable dimension that the above "two rectangles" don't account for. Need to know the pitch(es) of the roof if you are looking for a surface area measurement.Quote:
Originally Posted by Irving
Are you saying you measured from eve to ridge here? If so, and the pitch is consistent through out, then the rectangles method will work fine.Quote:
Originally Posted by Irving
It's Not Flat, stop trying new math on the problemQuote:
Originally Posted by HoneyBadger
Common Core math.Quote:
Originally Posted by davsel
http://www.kappit.com/img/pics/201509_1635_afece_sm.jpg
Don't worry Kazoo, I'm a rocket scientist. [LOL]Quote:
Originally Posted by Great-Kazoo
Knowing the rough size of the roof, this isn't actually that far off.Quote:
Originally Posted by Great-Kazoo
You have to find the area of each shape individually because of the slope. The measurements are actual, just drawn on an image that is "in scale" so it looks the same as if you were viewing the roof from a bird's eye view. I didn't measure eave to ridge, except for along the hips and valleys (which isn't helpful). A friend suggested that Wolframalpha can do this for me, and I may start using that program to save time.Quote:
Originally Posted by HoneyBadger
So how far off was my 1001sqft guestimate?
Well, I'd say over 900 sq/ft off, but I'm not sure I'm comfortable with the way I came to my answer. I'm going to see what wolframalpha says.
Uhhhhh wtf is the roof pitch?Quote:
Originally Posted by Irving
I'm laying in bed with my iPad after a few glasses of scotch. Math is a bit harder, but inventing things is easier... Got any niche problems that need solving?
So what was the roof pitch? Was it consistent throughout? That will make things easier.
The triangles you measured out are simple trig, but the other shapes are a bit tougher...
I was doing something wrong, so I'll have to use the Heron formula http://mathworld.wolfram.com/HeronsFormula.html.
If it was anything like a standard roof, (and now understanding how you got the measurements in your sketch) I'd guesstimate 1338 sqft.
The roof pitch is 5/12. How will you use that information to better solve the problem?
That is the most complicated way I've ever seen to derive the area of a triangle...Quote:
Originally Posted by Irving
Okay, now my guesstimate is 1320 sqft. [Neene3]Quote:
Originally Posted by Irving
When you say simple trig, would you say it's simple enough to do with a cell phone calculator, while standing on a roof? I'm not being sarcastic, that's an honest question.Quote:
Originally Posted by HoneyBadger
Show me how you're getting the area of the very top triangle with sides of 17, 17, 23.41.Quote:
Originally Posted by HoneyBadger
I'm on my iPad and can't do real math, but it should be...
hold the phone.... I can't trig on an iPad...
Oh hell... Without knowing at least one more angle measurement, I don't think I can do it.
Dammit. Math is telling me that your measurements don't add up.
Okay, well, the top triangle should be 144.5 sqft. (17x17)/2= 144.5. That's the easy one. I was getting sidetracked with the other shapes.
You can do simple math here because 17x17 tells you that the angle between them is 90 degrees. Just multiply to get the area of a 17x17 square, then divide by 2 to get half do that square.
Okay, I figured out exactly where I've been going wrong now. Thanks for playing along everyone.
I think we're lucky that triangle happened to be a right triangle. I've been getting 144 for that triangle as well.Quote:
Originally Posted by HoneyBadger
Everyone? This may as well be the PWT! [LOL]
Yep, right triangle is easy. I am still struggling with how to get some of the other shapes... I think you'd have to break them down into smaller triangles to get areas.Quote:
Originally Posted by Irving
Well, my iPad battery is down to 3%. Good luck. I'll check back in the morning to see how wrong I was... [ROFL1]
1400sqft of materials should cover it.
How is everyone finding the area of the parallelograms without the height measurement?
without taking height into it, I come up with 1256 st. ft. All I did was break it down into two boxes, one of 34.4' x 23.5' and the other 33.4' x 13.7'. No need to worry about all the other angles, except for the fact that they are adding height, you can figure that part out.[Coffee]
Jesus...not even 6am and I need a shot of bourbon already after reading this thread. Math sucks.