Question

We have angle 1=angle 2, angle2=angle 3. show that angle 1 = angle 3.

Answer 1

in triangles ABC and ADC.
angle 1 = angle 2 (given)
angle 2 = angle 3 ( given)
therefore,
angle 1 = angle 3
because,
both triangles base are same. so, angle 1 = angle 3.