Two parallel lines are cut by a transversal. Angles A and B are adjacent exterior angles. Angle A measures 87 degrees. What does Angle B measure?

Angle A + angle B must add up to 180°

so if angle A = 87°, then ....

B= 180 - 87

B= 93 degrees.. :)

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To find the measure of Angle B, we need to understand the relationship between adjacent exterior angles formed by parallel lines and a transversal.

When two parallel lines are cut by a transversal, four pairs of corresponding angles are formed: corresponding angles, alternate interior angles, alternate exterior angles, and adjacent exterior angles.

Adjacent exterior angles are formed when a transversal intersects two parallel lines, and the angles are on the same side of the transversal, outside the parallel lines.

The key property of adjacent exterior angles is that they are supplementary, meaning their sum is 180 degrees.

In this case, Angle A and Angle B are adjacent exterior angles. Given that Angle A measures 87 degrees, we can use the property of supplementary angles to find the measure of Angle B.

To do this, subtract the measure of Angle A from 180 degrees:
Angle B = 180 degrees - Angle A
Angle B = 180 degrees - 87 degrees
Angle B = 93 degrees.

Therefore, Angle B measures 93 degrees.