ACT study set

30 60 90 triangle - Side opposite 30 degree angle

x (smallest side)

30 60 90 triangle - Side opposite 60 degree angle

x√3 (medium side)

30 60 90 triangle - Hypotenuse

2x (largest side)

law of sines

a/sin A = b/sin B = c/sin C

law of cosines

c = √(a² + b² - 2ab cos C

law of cosines solved for other things

a² = b² + c² - 2bc cosA

b² = a² + c² - 2ac cosB

c² = a² + b² - 2ab cos C

combination equation

n = number of objects

r = objects selected each time

n!/(r!(n-r)!