One of the corners formed by two intersecting straight lines is 25 degrees. Find the values for the remaining angles.

Let the angles be numbered clockwise starting from the known.

Given:

1st corner = 25 gr.

Find: 2, 3, 4 corners.

Solution:

The vertical angles are equal, so the angle is 3 = 25 degrees.

The sum of adjacent angles is 180 degrees, so angle 2 (adjacent to angle 1) is equal to:

180 – 25 = 155 (gr.)

Angle 4 and 2 are vertical, so angle 4 = 155 degrees.

Answer: 25, 155, 155 degrees.