D and E are points on the sides CA and CB respectively of a triangle ABC right angled at C. Prove that AE2+BD2=AB2+DE2.
Open in App
Solution
Given: △ACB is a right angles triangle at C. Construction: Join AE,BD and ED. To Prove: AE2+BD2=AB2+DE2 Proof: In △ACE By pythagoras theorem, AE2=EC2+AC2.....(1) In △BCD By pythagoras theorem, BD2=BC2+CD2.....(2) In △ECD By pythagoras theorem, ED2=EC2+DC2.....(3) In △ABC By pythagoras theorem, AB2=BC2+AC2.....(4) Adding 1) and 2) we get, AE2+BD2=EC2+AC2+BC2+CD2......(5) From 3), 4) and 5) we get, AE2+BD2=AB2+DE2[henceproved]