"Tim Streater" wrote in message
...
In article ,
The Medway Handyman wrote:

An awning is attached to a wall at a height "X".


The front edge is lower because the awning slopes by 15 degrees.


Depending on the width, the awning could extend by anything from 1m to
4m.

If I want the front edge at a specific height "Y", what would distance
"X" be?

I want to make up a spreadsheet to calculate this for any height "Y" and
any extension. So, if the client wants the front of the awning 2.1m off
the ground and it extends 2m, how high would "X" be?

Well if it slopes 15deg then the angle it makes with the wall is 90-15 =
75deg. So if it extends out Z (which you say is 1m to 4m), then that's the
hypotenuse of the triangle in which case the vertical height of the
triangle is given by:

H / Z = cos 75

So:

H = Z * cos 75

But you said the front edge is up by 2.1m so that gives you:

X = 2.1 + H

or X = 2.1 + (Z * cos 75)

if Z=2 then I type this into Google:

2.1 + (2 * cos (75 deg))

and it gives me 2.617....


No need for a spreadsheet at all.

or even a calculator

cos (75) is 0.258

so rounding it down a bit it's

Y +0.25(Z)

tim