2. Lesson 8.3 Concept: How to classify triangles by their sides and angles. An equilateral triangle has three sides of the same length. An isosceles triangle has a least two sides of the same length. A scalene triangle has three sides of different lengths. 22 2 3 3 4 1 5 6

3. An acute triangle has three acute angles (less that 90 0 ). A right triangle has one right angle. (90 0) An obtuse triangle has one obtuse angle (more that 90 0). 60 0 120 0 30 0

4. Classify each triangle. 100 0 50 0 5 4 6 Obtuse, Scalene 78 0 44 0 57 0 6 5 5 Acute, Isosceles 60 0 6 6 6 Acute, Equilateral