Find the value of m°.

Solution:

The angles 25°, 78°, and m° are angles around a point on a straight line. Their sum is 180°.

\( 25° + 78° + m° = 180° \)

\( 103° + m° = 180° \)

\( m° = 180° - 103° \)

\( m° = 77° \)

Answer: 77