Question

18. Which angles are supplementary to _1? Which are congruent to 21? SEE EXAMPLE 1 5/6 7/8

Answer 1

Note that vertical angles and corresponding angles are congruent.

From the figure,

1 and 4 are vertical angles, they are congruent

1 and 5 are corresponding angles, they are congruent

5 and 8 are vertical angles, they are congruent

The remaining angles will be supplementary to angle 1.

To summarize :

Congruent angles to angle 1 are

4, 5 and 8