Find the value of A A. 450 B. 550 C. 400 D. 500

1.	Find the value of A A. 450 B. 550 C. 400 D. 500
Answer» Answer: 40° Step-by-step EXPLANATION: For convenience I've marked the DIAGRAM with point being named. Now, ∠YTP = 180° - 110° = 70° ∴ ∠QPT = 70° + 40° = 110° [∵ exterior ANGLE = SUM of other two ANGLES] Now, ∠UPQ = ∠UQP = 180° - 110° = 70° Now, ∠A = 180° - (70° + 70°) = 40° [angle sum theorem]

Answer»

Answer:

40°

Step-by-step EXPLANATION:

For convenience I've marked the DIAGRAM with point being named.

Now, ∠YTP = 180° - 110° = 70°

∴ ∠QPT = 70° + 40° = 110° [∵ exterior ANGLE = SUM of other two ANGLES]

Now, ∠UPQ = ∠UQP = 180° - 110° = 70°

Now, ∠A = 180° - (70° + 70°) = 40° [angle sum theorem]

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