Exercise 8 Page 444

Two angles are vertical angles when their sides form two pairs of opposite rays. Using this fact, we can create a conditional statement. If ∠ JMF and ∠ HMG are vertical angles, then their sides form two pairs of opposite rays. We will proceed by labeling the relevant angles and marking the rays that create each of the angles.

Are the rays opposite? Yes! Because M is the point of intersection for lines FH and JG, we know that they form opposite rays. Therefore, ∠ JMF and ∠ HMG are vertical angles and the statement is true.