1. Triangles Chapter 4 Section 1

2. Triangles have 3 sides (legs) 3 angles (vertices)

3. Classify Triangles by side 3 sides congruent ---- Equalateral 2 sides congruent -----Isosceles No sides congruent ---- Scalene

4. Classify Triangles by Angle All Angles Acute ----- Acute One Angle Obtuse ----Obtuse One angle Right ---- Right

5. Isosceles Triangles The Angle that connects the two congruent sides is called the VERTEX ANGLE Vertex Angle

6. Only Isosceles triangles have Vertex Angles Triangle FGH has vertex angle G FGH is isosceles FG is congruent to GH

7. The remaining angles are called Base Angles Triangle FGH has vertex angle G Angles F and H are Base Angles Vertex Angle Base Angles

8. Triangle BGM has vertex angle B BG = 3x + 4 MB = 4x – 6 GM = 5x – 8 Find x Find BG, MB and GM

9. Right Triangles Right Triangles have one right angle The other two angles must be acute The side opposite the right angle is called the HYPOTONUSE The hypotenuse is the longest side of a right triangle The other two sides are called legs

10. Right Triangle Right Angle Leg LegLeg Hypotenuse

11. Triangle PFE has Hypotenuse FE Angle F = 4x - 10 Angle E = 3x - 40 Angle P = 5x -10 Find x Find angles F, E and P

12. Page 183 Problems 1, 6,7,8 Problems 16 -23 Problems 33-41