Question

If in any triangle ABC, the base BC is produced in both ways the sum of the exterior angles at B and C is

Answer 1

Step-by-step explanation:

Let the exterior angles be x and y

so we need to find x+y

Now x = angle A + angle C......(i)

y= angle A + angle B...(ii)

Add (i) and (ii)

x+y= angle A + angle B + angle C + angle A

= 180° + angle A

Hence x+ y = 180° + angle A