Triangle Formulas

law of cosines

a^2 = b^2 + c^2 - 2bc(cosA)

cos =?

adj/hyp

cot =?

adj/opp

herons formula

area = √s(s-a)(s-b)(s-c) s = 1/2(a+b+c)

sec =?

hyp/adj

csc =?

hyp/opp

tan =?

opp/adj

sin =?

opp/hyp

law of sines

sinA/a = sinB/b = sinC/c

45-45-90 triangle

√2-√2-2

cos45

√2/2

sin45

√2/2

cos30

√3/2

sin60

√3/2

30-60-90

1-√3-2

cos60

1/2

sin 30

1/2

area formula

1/2abSinC 1/2cbSinA 1/2acSinb