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Very Basic Maths Question

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just as an aside....a 15.73 metre length of single pitch roof at circa 22 degrees angle is a helluva long piece of roof AND at quite a low angle...

ie too much snow on it in winter and it might be in danger of collapse? just a thought whilst I pace up and down the room worrying about the future of human life xD

Unless..... AHA it is 1.573 meters long.......to assume makes an ass and of u and mainly ME!!!

Edited by 5min OCD speculator
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34 minutes ago, crashmonitor said:

Gradient and angle are two different results. When one refers to a pitch is that the gradient ( as in road signs) or the angle?  Probably angle..gradients are %:S

This discussion made me Google what the percentages on the signs mean in degrees. Looks like the angle = inverse sine of gradient on the sign

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56 minutes ago, Bear Hug said:

I get 22.9 degrees

Arcsin (610/1570)

As a check, sin 30 degrees is 0.5, so that angle is definitely smaller than 30

That sounds spot on. I thought 38 was wrong. My tiles go down to 22.5 degrees and we’ve been having issues with the original roofer as to whether the tiles weren’t actually suitable to use.

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Posted (edited)
2 minutes ago, 5min OCD speculator said:

cool, I like the side window! Not so sure about that thing on the wall :P

Arghh the cat bed. It was in permanent use a few months back but they can’t be bothered with it now.

Edited by Battenberg
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Tangent = O/A = 610/1450 = 0.42 … invert tan with arcrtan function (change number to degrees) = 22.81 degrees

C = A/H = 1450/1570 = 0.92 … invert S = 22.5 deg

S = 610/1570 = 0.388 = 22.86 deg

Differences due to errors in length measurement.

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1 hour ago, Battenberg said:

I’m sorry. I’m being really thick but I’m trying to calculate the pitch of my roof.

I have the following and make the answer 38 degrees but I’m not convinced I’m correct.

Could someone please check it for me. 




X = 22.863 degrees


It's not quite a right angled triangle so you have to use the sine rule rather than SOHCAHTOA/arcsin to solve it.

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