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  1. In the given figure, the side BC of a Δ ABC is produced on both sides. Then ∠ 1 + ∠ 2 is equal to :


    1. ∠A + 180°
    2. 180° − ∠A
    3. 1(∠A + 180°)
      2
    4. ∠A + 90°
    5. None of these
Correct Option: A

From the given figure, In ΔABC
We know that , Exterior angle = Sum of two interior angles
∠1 = ∠A + ∠5 ................. ( 1 )
and ∠2 = ∠A + ∠6 ................. ( 2 )
Adding equations ( 1 ) and ( 2 ).
∠1 + ∠2 = 2∠A + ∠5 + ∠6
= 2∠A + (180° − ∠A) = ∠A + 180°
The given question can be restated as the sum of two exterior angles exceeds ∠A of the ΔABC by 2 right angles.



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