Question

Se considera triunghiul dreptunghic ABC , m(A) = 90 grade . Daca AB = 9 cm si BC=15 cm , calculati AC , sin B , cosB , tgC si ctgC .

Ajutorrr , va rog . 

Answer 1

BC²-AB²=AC²⇒AC²=15²-9²
                       AC²=225-81
                       AC²=144
                       AC=√144
                       AC=12cm
sinB=co/ip⇒sinB=AC/BC⇒sinB=12/5⇒sinB=4/5
cosB=ca/ip⇒cosB=AB/BC⇒cosB=9/15⇒cosB=3/5
tgC=co/ca⇒tgC=AB/AC⇒tgC=9/12⇒tgC=3/4
ctgC=ca/co⇒ctgC=AC/AB⇒ctgC=12/9⇒ctgC=4/3