# Angles in Triangles

- Author:
- Sarah, Tim Brzezinski

## Vertical Angles Theorem

## Vertical Angles Questions

1) Complete the following statement (based upon your observations).
Vertical angles are always __________________________.
2) Suppose the pink angle above measures 140 degrees. What would the measure of its vertical angle? What would be the measure of the other 2 (gray) angles?

## Exterior Angle Theorem

In the applet above, an exterior angle of a triangle is shown.
The pink angle and green angle are referred to as

*remote interior angles*with respect to this exterior angle. What can you conclude about the measure of an exterior angle of a triangle with respect to its*2 remote interior angles?*What other theorem is readily made obvious here?