Answer:
m∠A = 91°
Step-by-step explanation:
∠A ≅ ∠B (Vertical Angle Theorem). This means that the two angles will have the same measurements.
Note that a straight line = 180° (Definition of a Straight Line).
Find the value of m∠B.
180 - 47 - 42 = m∠B
m∠B = 180 - (89)
m∠B = 91°
Remember that ∠B & ∠A are vertical angles, so they will have the same measurement.
m∠A = 91°
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