Answer:
∠1 + ∠2 + ∠3 = 180°
Step-by-step explanation:
Given : AB II XC
To Show : ∠1 + ∠2 + ∠3 = 180°
Proof: Here, given that AB is parallel to the line XC
⇒ ∠4 = ∠2 (Pair of Alternate angles as AB II XC) ......... (1)
and ∠5 = ∠3 (Pair of Alternate angles as AB II XC) ........... (2)
Now, ∠1 + ∠4 + ∠5 = 180° ( Straight Angle)
But, from above (1) and (2)
∠1 + ∠2 + ∠3 = 180° ( as ∠4 = ∠2, ∠5 = ∠3)
Hence, ∠1 + ∠2 + ∠3 = 180°
Hence Proved.