Students will learn to classify triangles by either their angle measures or side lengths. There are three types of triangles defined by their angles: acute, obtuse, and right. There are also three types defined by their sides: equilateral, isosceles, and scalene. Examples of each type are provided. The document also reviews that the sum of the interior angles of any triangle is always 180 degrees.

1. Learning Target:Students will learn how to classify triangles using their angles measures and by using their side lengths.

2. Remind me what the degrees are of an acute, obtuse, right and straight angle.

3. There are two main ways to classify triangles… Either by it’s angles or it’s sides.

4. Classifying Triangles by Angleshttp://kensmathworld.com/videos/classifying.png

5. Equilateral Triangle:All three sides of the triangle are the same length.http://www.mathwarehouse.com/geometry/triangles/images/equilateral-tiangle.jpg

6. Isosceles Triangles:Two sides of the triangle have the same lengths.http://image.wistatutor.com/content/feed/u984/isosceles.jpg

7. Scalene Triangle:All three sides of the triangle have different lengths.http://www.printable-math-worksheets.com/images/Scalene_Triangle.gif

8. http://www.glogster.com/media/4/28/54/52/28545238.gif

9. Classify the triangle by its angles.Classify the triangle by its sides.Examples on pg. 472

10. How many degrees are in a triangle?

11. How many degrees are in a triangle?A: Every triangle, no matter the size or configuration, is made up of 180 degrees.

12. Tell whether the three angle measures could be the measures of a triangle. Justify your answer.1.) 10, 70, 802.) 18, 23, 139

13. Tell whether the three angle measures could be the measures of a triangle.1.) 10, 70, 80 – No because the sum of the angles are 160 degrees.2.) 18, 23, 139 – Yes because the sum of the angles are 180 degrees.

14. Can you classify triangles using their angles measures and by using their side lengths?