ΔABC
AD inaltime
a)AΔ=BC ×AD/2=4 ×6/2
=24/2
=12 cm²
b)Aici efectuam transformarile:BC=20mm=2cm
AD=0,3 dm=3 cm
Astfel:AΔ=AD × BC/2
=2 × 3/2
=3cm²
c)AΔ=AD × BC/2
=40cm × (3/5 × 40cm)/2
=40 cm × 24cm/2
=40 ×12
=480 cm²
d)AΔ=BC × AD/2
=(20% × BC) ×BC/2
=(1/5 × 10 × 10)/2
=2 ×10/2
=10cm²