From the figure, let's find the missing measures.
• m∠e
Angle e is vertically opposite to the measure 66°
Applying the vertical angles theorem, both angles are congruent.
Thus, we have:
e = 66°
• m∠f:
To find the measure of angle f, apply the angles on a straight line theorem.
Angles on a straight line are supplementary ans supplementary angles sum up to 180 degrees.
Angle F and angle e are on a straight line.
Thus, we have:
m∠e + m∠f = 180
m∠f = 180 - m∠e
m∠f = 180 - 66
f = 114°
• m∠d
Angle d is a right angle. Thus, the measure of angle d is 90 degrees.
d = 90°
ANSWER:
• d = 90,°
,
• e = 66,°
,
• f = 114°