Bellwork Classify each angle as acute, obtuse, or right. 90° 72° 116° How do you know that ? 1 2
Apply Triangle Sum Properites Lesson 4.1 Apply Triangle Sum Properites
Objective Students classify triangles and find measures of their angles.
Standard 12.0 – Students find and use measures of sides and of interior and exterior angles of triangles and polygons to classify figures and solve problems 13.0 – Students prove relationships between angles in polygons by using properties of complementary, supplementary, vertical, and exterior angles.
Academic Language Triangles Interior angles Exterior angles Scalene, isosceles, equilateral, acute, right, obtuse, equiangular Interior angles Exterior angles Corollary to a theorem
Think/Pair/Share Right, obtuse, acute, equilateral, isosceles, and equiangular
Triangle Polygon with 3 sides A B C
The Real World!
Practice
Interior vs. Exterior……….Angles
Prove
Example
Homework p.221 #1 – 7, 10, 15, 19, 21 – 26, 29