Question

Please solve it fast it's urgent

Answer 1

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Here is the solution:

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We draw a line PQ across angle c such that PQ // AB // DE

⇒ ∠B is spilt into B1 and B2 (See Attached)

Find B1:

∠A + ∠B1 = 180 (Opposite angles in a parallel segment)

∠B = 180 - ∠A

Find B2:

∠B2 = ∠C (Alternate angles)

Find ∠B:

∠B = ∠B1 + ∠B2

∠B = 180 - ∠A + ∠C

Find ∠A + ∠B - ∠C:

∠B = 180 - ∠A + ∠C

Add ∠A - ∠C to both sides:

∠A + ∠B - ∠C = 180

Answer: (C) ∠A + ∠B - ∠C = 180