Question

9. An exterior angle of angle ABC is angle ACD. Prove that angle A + angle B= angle
ACD​

Answer 1

Step-by-step explanation:

by the angle sum property of the triangle,

a+b+c=180

a+b=180-c

a+b=180-[180-ACD](c+ACD=180,linear pair)

a+b=180-180+ACD

a+b=ACD