Grab a red pen and have your homework

� Grab a red pen and have your homework out ready to grade

� Follow the directions in the handout we will discuss together

• Triangle Sum Theorem: The sum of the measures of the angles of a triangle is 180°. 1 2 3 _______ + _______+ ______= ____

�A corollary to a theorem is a statement that can be proved easily using theorem.

� Corollary to the Triangle Sum Theorem: The acute angles of a right triangle are complementary. ____ + _____ = ____

� Interior angle: angle inside the triangle � Exterior angle: angle formed when one side of a triangle is extended *Only one at each vertex

� Exterior Angle Theorem: The measure of an exterior angle of a triangle equals the sum of the measures of the 2 remote interior angles. § _____ + _____ = ______

Find the measure of <1, <2, and <3 1 62° 2 3

� Grab a ruler from the clear bin on the counter and partner up with one other person (groups of two)

� Warm-up � Objective: TLW define the Sum of angles in a triangle theorem and apply it along with the corollary to problems � Activity-Sums of angles in a triangle � Class practice problems

� Now on your own you and your partner are to each cut one more triangle � Repeat the steps of the activity and see if it holds true for triangles that you created on your own

� Grab a blank sheet of notebook paper