In the given figure, ∠ACB=90o and CD⊥AB.
Prove that BC2AC2=BDAD.
On △ABC and △ACD
∠ACB=∠CDA,
∠CDA=∠CAB
ΔABC and ΔACD are similar
ACAB=ADAC
AC2=AB×AD
Similarly, ΔBCD and ΔBAC are similar.
BCBA=BDBC
BC2=BA×BD
BC2AC2=AB×BDAB×AD
∴BC2AC2=BDAD