# In a #DeltaABC#, right angled at #A#, a point #D# is on side #AB#. Prove that #CD^2=BC^2+BD^2#?

##### 1 Answer

Dec 6, 2016

#### Explanation:

With a point

In the right angled triangle

=

or

=

#AD^2+AC^2+2BD^2+2xxBDxxAD# =

#CD^2+2BD(BD+AD)# =

#CD^2+2BDxxAB#

or