Answer:
Explanation:
Given the angles 21° and 92° where three lines are coincident, you want the measures of angles d, e, and f.
Vertical angles
Angles on opposite sides of the point where lines cross are vertical angles. They share a vertex, and are formed from opposite rays. They are not adjacent. Vertical angles are congruent.
Here, the angle marked d is a vertical angle with the one marked 92°. The angle marked e is a vertical angle with the one marked 21°
Linear angles
A linear angle is a straight line. Its angular measure is 180°. Here, the angles d, e, and f add up to form a linear angle:
d + e + f = 180°
92° +21° +f = 180°
f = 180° -113°
f = 67°