On Sun, 09 Apr 2006 08:35:04 -0500, Dave Nay
davedotnay@vidanaydotcom wrote:

Gerald Ross wrote:
I want to build a right triangle, 30 deg. 60 deg. angles without using a
protractor (don't have one). The long arm will be 24 inches and will be
using a square for the right angle. Anyone know the formula to get the
length of the short side? I can figure out the hypotenuse for a double
check of squareness.

Geometry is in my misty past by over 50 years.

The short side is long side/2

The medium side is short side x square root of 3.

These only apply for 30-60-90 triangles.

For your situation, the shortest side is 24"/1.732 = 13.857

That's possibly the way I'd do it, thanks to Pythagoras ...or go out
and buy a protractor, or compasses. I prefer compasses [or a trammel]
for specific angles like that [you can have, or make large ones and
get better accuracy over distance].

Or, having a computer to be able to post here, there is CAD. Print a
sheet with the angle, fold along the lines and use as a template.

Or there is a way to trisect an angle [approximate, but not that you'd
notice] using the square. So a 30 degree angle is possible. All
physical measures are inherently approximate even if not in theory, so
it would do.