As
△ADC is right angled at D
So applying Pythagoras theorem states that AC2=AD2+DC2
b2=h2+(a−x)2
b2=h2+a2+x2−2ax (1)
Hence (i) proved.
Also, △ADB is right-angled at D.
So applying Pythagoras theorem states that c2=h2+x2 (2)
Substituting (2) in (1)
b2=h2+x2+a2−2ax
b2=(h2+x2)+a2−2ax
b2=c2+a2−2ax
b2=a2+c2−2ax
Hence (ii) proved.