Question

elect a value to tell how each pair of angles is related.

Two lines that intersect forming 4 angles. Starting from the top angle and moving clockwise, the angles are labeled 1, 2, 3, and 4.

Answer 1

For two lines intersecting with angles labeled clockwise 1 (top), 2 (right), 3 (bottom), 4 (left):

- Vertical (opposite) angles: ∠1 and ∠3 are equal; ∠2 and ∠4 are equal.
- m∠1 = m∠3, m∠2 = m∠4.

- Adjacent angles (sharing a side) are supplementary (sum to 180°):
- m∠1 + m∠2 = 180°, m∠2 + m∠3 = 180°, m∠3 + m∠4 = 180°, m∠4 + m∠1 = 180°.

If m∠1 = x, then m∠3 = x and m∠2 = m∠4 = 180° − x.