AD²=BD×DC
AB²=BD×BC
AD²/DC=BD×DC/DC=BD
AB²/BC=BD×BC/BC=BD
rezulta ca
AD²/DC=AB²/BC
b)
A=8x8√2/2=32√3
BC=√[8²+(8√3)²]=√64+192=√256=16
A=BCxAD/2
32√3=16xAD/2
AD=64√3/16=4√3
c)
BD=√[8²-(4√3)²]=√64-48=√16=4
DC=√[(8√3)²-(4√3)²]=√192-48=√144=12
A ΔADC = 12x4√3/2=24√3
A ΔABD = 4x4√3/2=8√3
raportul dintre arii= 24√3/8√3=3