Question

In triunghiul ABC AB=AC=6 m(b>)=75 grade
Calculeaza aria triunghiului ABC

Answer 1

A tr=AB•AC•sin A/2 AB=AC=6 cm m(B)=m(C)=75 Rezulta m(A)=180-2•75=30 Rezulta A=6•6•1/2/2 A=18/2 A=9 cm^2

Answer 2

$A_{\triangle ABC}=\frac{AB\cdot AC\cdot sinA}{2}$
m(<B) = 75°
m(<C) = m(<B) = 75°
m(<A) = 180° - (75°+75°) = 180° - 150° = 30°

sin A = sin 30 = 1/2
$A_{\triangle ABC}=\frac{6\cdot6\cdot\frac{1}{2}}{2}=\frac{18}{2}=9$