Geometry — Formulas to Know Cold

Triangle: Area = 1/2 base x height. Angles sum to 180.

Right triangle: a2 + b2 = c2 (Pythagorean theorem)

Special right triangles:

30-60-90: sides = x, x sqrt(3), 2x

45-45-90: sides = x, x, x sqrt(2)

Circle:

Area = pi r2

Circumference = 2 pi r

Arc length = (angle/360) x 2 pi r

Sector area = (angle/360) x pi r2

Rectangle: Area = lw, Perimeter = 2l + 2w

Cylinder: Volume = pi r2 h

SAT tip: Draw a picture for every geometry problem. Label everything. If they don't give you a figure, make your own.

Reference:

Wikipedia: Geometry

https://en.wikipedia.org/wiki/Geometry