Formulas from Algebra and Geometry

triangles

Area = 1 bh
       2

law of cosines

c² = a² + b² - 2abcosC

Pythagorean Theorem

a² + b² = c²

equilateral triangle
             ___
A = s²(3)
      4

Rectangles

A = bh

parallelograms

A = bh

trapezoids

A = 1 h(b₁ + b₂)
2           

ellipses

A = ab
                                     __________
Circumference = 2 ((a² + b²)/2)

cones

V = 1r²h
     3      

Area = r²

Circumference = 2r

Spheres

V = 4r³
     3    

Surface Area = 4r²