Răspuns:
a) A(∆ABC)=60√3cm²
b) A(∆ABC)=30cm²
c)A(∆ABC)≈26,14cm²
Explicație pas cu pas:
a)
A(∆ABC)=1/2*AB*BC*sin<B
sin60°=√3/2
A(∆ABC)=1/2*12*10*√3/2=60√3 cm²
b)
A(∆ABC)=1/2*AC*BD=1/2*10*6=30cm²
c)
A(∆ABC)=√((p(p-AB)(p-AC)(p-BC))
p=(AB+AC+BC)/2=(6+9+12)/2=27/2=13,5cm
A(∆ABC)=√((13,5(13,5-6)(13,5-9)(13,5-12))=
=√(13,5*7,5*4,5*1,5)=√683,4375≈26,14cm²
