Formula List: Please add to it

[okGMAT]

Geometry formulas that may come in handy (π = pi (alt+227); ² = alt+0178):

For a Square:
A= L*W
Perimeter= 2L+2W

For a Triangle:
A=.5(B)(H)

For a Circle:
A= πr²
C= 2πr

Volume of cube = L*W*H
Volume of a Cylinder= πr²*h
Volume of a pyramid= (1/3)πr²(h)

If anyone can help me with properties of triangles I'd appreciate it. Math is not my strong suit. Just copy and paste what I started and add to it.
-Thanks