Question

In isosceles ∆ABC,AB=AC .The side BA is produced to D such that BA = AD. Prove that in
<BCD = 90;​

Answer 1

Answer:

in triangle abc , ab = ac then ac ad hence, acd = adc now, let abc = acb x and acd = adc = y soo , abc + bcd = bdc = 180 abc + acb + acd + bdc = 180 x+x+y+y = 180

2 ( x+ y ) = 180

x + y = 90

acb + acd = 90

bcd = 90