Maths!!

[dickbastardly]

Ok you remember at school when you were being taught maths and the teacher started talking about pie and all that lot? Well i remember and decided that i would never have to use that in my life!!! well in fairness i havent needed it this long so i havent done bad!!
My question!!
I am about to build a rear extension, and need to know how far i can come out on a roof pitch of 18 degrees.
The facts i know:
Height to rear window = 3765mm
minus 150mm to cut in the lead = 3615mm
minus the height of the new wall of 2400mm = 1215mm drop
the angle of the roof will be 18 degrees.
thems the facts. how do i work out the distance i can come out??
so how many mm do i drop per meter out?
A pie to the winner!!
Andy

[_rubinho_]

I don't quite understand your explanation of the first part of the question but for the second part, for every metre you go out the roof will drop ~32.5cm. For the record to work it out the drop is the length of the extension multiplied by the inverse tan of 18 degrees. The inverse tan will look something like tan-1 on a pocket calculator. There is an Inv tick box and tan button on the standard calculator which comes with Windows.

[dickbastardly]

Thanks for that.
so based on your figures i could go out from the house 3692mm (drop of 1200 devided by 325mm)?
andy

[_rubinho_]

Within 1mm yes, absolutely right.

[The Moose]

dickbdly said:

Ok you remember at school when you were being taught maths and the teacher started talking about pie and all that lot?

I knew this was going to go well when I read you talking about pi

[dickbastardly]

Thanks guys
You know the worst think is....i remember so little about maths at school the calculations could be completely wrong but i am going to build to them!!
I tried to google it but no luck!
o well i am sure someone will let me konw if the calcs are wrong!!
Cheers
Andy

[eldudereno]

Don't you work from plans round your way then?

[dickbastardly]

Well Rubinho
thanks.
Not that i didnt trust you i just dont understand maths that much!!
i found this: http://www.analyzemath.com/Geometry_calculators/ri...
the third calculator worked it out a treat!!
well just like you did really!!
Cheers
Andy

[dickbastardly]

Not got to the plans stage just yes.
that will be the next thing.
Cheers
Andy

[mcflurry]

pi would only be of use if you had a round roof

[Eric Mc]

We only learned about "pie" in Domestic Science classes.