1. teorema inaltimii ADpatrat=BDxDC=5x12, AD=rad60
2. BD=5, DC=9, BC=BD+DC=5+9=14
t. catetei ABpatrat=BDxBC=5x14, AB=rad70
Acpatrat=CDxBC=9x14, AC=3rad14
3. triunghi drepunghic isoscel catetele sun egale se aplica t lui Pitagora
BCpatrat=ABpatrat+ACpatrat=16+16=2x16, BC=4rad2
