Angles in Triangles
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?