Opposite Angles

Opposite Angles

Before the next rules can apply, there must be two parallel lines (p & q) and a transversal (t).

symbols:

< angle @ congruent

Each time the transversal t crosses a parallel line, two sets of opposite angles are formed.

Line p:

<1 @ <4 and <2 @ <3

Line q:

<5 @ <8 and <6 @ <7

Angle 1: Angle 2:

• Drag points A or B to change the direction of the lines • What happens to the measures of the "vertical angles"?

If two angles are vertical, then their measures are equal.

Vertical Angles Conjecture:

These angles are said to be "vertical".