Could someone explain a). there is an attachment

All of these angles can be compared to each other.

There are:

- Alternate interior angles

-- Angles that share one line and two parallel lines and are less than 90 degrees (angles 10, 12). These angles are equal to each other.

- Alternate exterior angles

-- Angles that share one line and two parallel lines and are more than 90 degrees (angles 1,5) These angles are equal to each other.

- Vertical Angle

-- Angles that share a point and are opposite of that point (angles 2,3) These angles are equal to each other.

-Supplementary angles

-- Angles that are on the same side of one line and share the side of another (angles 9,10). These angles are always equal to 180 degrees.

Using this we know:

a. m of angle 5 = to the m of angle 3 = 102

m of angle 5 = 102 degrees