Question 982347
*[illustration median].

AD^2= AE^2+DE^2

AE= sqrt(3)AC/2

AE^2= 3AC^2/4

AC=BC

AE^2 = 3BC^2/4

But BC = 4DC

AE^2 = 48DC^2/4 

AE^2= 12DC^2

DE^2= (CE-CD)^2

But CE = BC/2
But BC= 4DC
SO CE = 2DC

DE^2= (2DC -DC)^2

= DC^2



SO AD^2 = 12CD^2 +DC^2

=13DC^2

AD^2 =13CD^2