Hello prantik007My thanks to sa-ri-ga-ma for his contribution so far. He is quite correct up to the point where he says:But I'm afraid that this might be a bit of a cop-out.Hence you can show that
D is mid point of AB
I think you also need to use the fact that . Then use the fact that to say that:Now we have established that , it's very easy to show that 's and are congruent, and hence that .
(angle sum of )
Can you fill in the details now?
Grandad