Answer:
3, 4, 5
Explanation:
You have parallel lines crossed by a transversal, and one obtuse angle marked as 99°. You want the angle designators of the congruent angles.
Congruent angles
Where a transversal crosses parallel lines, corresponding angles are congruent. In this figure, angle 3 corresponds to the one marked 99°, so it is congruent.
Anywhere that lines cross, vertical angles are congruent. Angles 3 and 4 are vertical angles, as are angle 5 and the one marked 99°.
Hence angles 3, 4, 5 are all congruent to the one marked 99°.
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Additional comment
You may have observed that the listed congruent angles are all of the obtuse angles in the figure. Similarly, all acute angles in the figure are congruent. Since the acute and obtuse angles are supplementary (form linear pairs), angles 1, 2, 6, 7 are all 81°.