Lines a and c are parallel. Find all angles if angle 1 = 78 *

It is known from the condition that lines a and c are parallel and they are intersected by a secant.

We need to find all the angles formed at the intersection of two parallel secant lines, if the angle 1 = 78 °.

The drawing in the condition is not given to us, but it will not be difficult to find it on the Internet.

Find the degree measure of angle 4 as an adjacent angle (the sum of adjacent angles is 180 °).

angle 4 = 180 ° – 78 ° = 102 °;

angle 3 = 78 ° (as crosswise).

angle 2 = 180 ° – 78 ° = 102 °;

angle 4 = angle 6 = 102 ° as internal crosswise at parallel lines

angle 3 = angle 5 = 78 °;

angle 5 = angle 7 = 78 °;

angle 6 = angle 8 = 102 °.