An illustration shows two parallel slanting lines m and l intersecting a vertical line k.
The angles formed at the intersection of lines l and k are 1, 2, 4, and 3.
The angles 1 and 4 are opposite to each other while angles 2 and 3 are opposite to each other.
The angles formed at the intersection of lines m and k are 5, 6, 8, and 7.
The angles 5 and 8 are opposite to each other while angles 6 and 7 are opposite to each other.
What is m∠1 if m∠4=25° ?