Question

Select all pairs of angles in the figure above that are supplementaryA <1 and <7B <1 and <8C <3 and <6D <4 and <7

Answer 1

Solution

Notice that angle 1 and angle 8 are alternate interior angles

Hence,

$\angle1=\angle8$

Notice that angle 8 and angle 7 are supplementary angle

Since angle 1 is equal to angle 8 it follows

Angle 1 and angle 7 are supplementary

Angle 1 and angle 3 are vertically opposite angle

Hence

$\angle1=\angle3$

This implies that