If the sides of a triangle are produced then the sum of

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If the sides of a triangle are produced then the sum of the exterior angles i.e., ∠ a + ∠ b + ∠ c is equal to :

1. 180°
2. 90°
3. 360°
4. 270°
5. None of these

Correct Option: C

From above figure , we have
Since every exterior angle is equal to sum of interior opposite angles,
So, ∠ a = A + B, ∠ b = B + C and ∠ c = A + C
We know that , A + B + C = 180°
∴ ∠a +∠b + ∠c = 2(A + B + C) = 2 × 180° = 360°.