Answer:
D. 115 deg
Explanation:
Look at just the two lines that intersect forming angles 5, 6, 7, and 8.
When two lines intersect at a point, they form 4 angles. Each pair of angles that are opposite each other, such as the pair of angles 5 and 8 and the pair of angles 6 and 7, is called vertical angles. Angles 5 and 8 are vertical angles. Angles 6 and 7 are vertical angles.
Theorem:
Vertical angles are congruent.
If two angles are vertical angles, they are congruent. This means that their measures are equal. Angles 5 and 8 are vertical angles and congruent. Their measures are equal. Since the measure of angle 8 is 115 deg, then the measure of angle 5 is also 115 deg.
Answer: Choice D: 115 deg