4. Classifying Triangles How many degrees can be found in all triangles? 180 We can classify triangles 2 ways: By their angles By their sides

5. Classifying by Angles: Acute Triangle What is an acute angle? An acute triangle has all three angles less than 90 degrees

6. Classifying by angles: Right Triangle What is a right angle? How many right angles can be found in any triangle? 1 A right triangle has 1 right angle. The side opposite the right angle is called the hypotenuse.

7. Classifying by angles: Obtuse Triangle How many obtuse angles can be formed in any triangle? 1 An obtuse triangle has one obtuse angle: The longest side is opposite the obtuse angle

8. Classify each triangle Acute Obtuse Right Obtuse Right

9. Classifying by sides: Equilateral Triangle An equilateral triangle has all three sides equal An equilateral triangle is also an equi-angular triangle. How large is each angle? 60 degrees

10. Classifying by sides: Isosceles Triangle An isosceles triangle has 2 equal sides An isosceles triangle also has 2 equal angles at the base which are opposite the equal sides

11. Classifying by sides: Scalene Triangle A scalene triangle has no equal sides How many angles can be equal in a scalene triangle? 0

12. Classify: Isosceles Scalene Equilateral

13. Find the missing angle: 100 45 45 3060 40