extend previous knowledge of triangles and their properties to include the sum of angles of a triangle, the relationship between the lengths of sides and measures of angles in a triangle, and determining when three lengths form a triangle

How Do You Determine Whether a Triangle Can Be Formed Given Three Side Lengths?

If you're given 3 side measurements, there's a quick way to determine if those three sides can form a triangle. Follow along with this tutorial and learn what relationship these sides need in order to form a triangle.
How Do You Put the Sides of a Triangle in Order According to Size if You Know Two Angles of the Triangle?

Trying to figure out which side of a trianlge is the shortest? How about the longest? All you need to get your answer are the angle measurements of the triangle! How does it work? Watch this tutorial to find out!
What is the Triangle Sum Theorem?

When you're dealing with triangles, the Triangle Sum theorem can be very useful in finding interior angle measurements. In this tutorial, learn how to find this helpful theorem!