# Triangle Review

## Triangle Types

Use the interactive animation below to manipulate vertex "C". Try to form the 6 triangle types from above.

## Interior Angles of a Triangle

Recall that the interior (inside) angles of a triangle add up 180 . Manipulate the triangle below to verify.

## Summary

## Exterior Angles of a Triangle.

There are two exterior (outside) angle relationships to consider for triangles. For the first relationship, the exterior angles of a triangle all add up to 360 .

In the second relationship, an exterior angle equals the sum of the two opposite interior angles. Use the animation below to illustrate. In the animation below, drag Point A (or BAC) to verify. For the second animation, drag the slider to visually observe the relationship.