in fig 17:
BC=CD+BD=20 CM
delta ABC dr , AC=cateta (prin teorema catetei)=> AC²=CD•BC=> AC²=4•20=>AC²=80=>AC= radical din 80=4 radical din 5. cm=> x=4 radical din 5. cm
fig 18 :
teorema catetei => ab²=db•bc => 144=9• x=>x=16 cm
fig 19:
teorema inaltimii =>x²=cd•bd=>x²=144=>x=12cm
fig 20:
teorema inaltimii => ad²=cd•x=>144=6•x=>x=24cm
fig 21
teorema lui pitagora => ac²+ab²=x²=> 64+225=x²=> x²=289=>x=17 cm.
fig 22
teorema lui pitagora=>x²+ab²=cb²=> x²+900=1156 => x²=256=> x= 16 cm.
