1.
a)Aria triunghiului=B·h/2;AD=h;BC=B⇒A=B·h/2=4·6/2=12cm²
b)BC=20mm=2cm;AD=0,3dm=3cm⇒A=B·h/2=3cm²
c)AD=40cm;BC=3/5·AD=3/5·40=24cm⇒A=B·h/2=480cm²
d)BC=1cm;AD=20/100BC=2/10BC=0,2cm⇒A=B·h/2=0,2cm²
2.
a)Aria triunghiului dreptunghic=C₁·C₂/2=4·6/2=12cm²
b)Triunghiul=dreptunghic isoscel;C₁=6 cm⇒C₂=C₁=6cm;Aria=C₁·C₂/2=18cm²