← Trigonometriset funktiot · Lukion taulukot · Trigonometriset funktiot (Trigonometria) →
1. sin α = a c {\displaystyle \sin \alpha ={\frac {a}{c}}}
2. cos α = b c {\displaystyle \cos \alpha ={\frac {b}{c}}}
3. tan α = a b {\displaystyle \tan \alpha ={\frac {a}{b}}}
4. α = 90 ∘ − β {\displaystyle \alpha =90^{\circ }-\beta }
5. a 2 + b 2 = c 2 {\displaystyle a^{2}+b^{2}=c^{2}}
6. Ala A = 1 2 a b {\displaystyle A={\frac {1}{2}}ab}
1. Sinilause
2. Kosinilause
3. Ala A = 1 2 a b sin γ = 2 r 2 sin α sin β sin γ = p ρ {\displaystyle A={\frac {1}{2}}ab\sin \gamma =2r^{2}\sin \alpha \sin \beta \sin \gamma =p\rho } , missä p = 1 2 ( a + b + c ) {\displaystyle p={\frac {1}{2}}(a+b+c)} .