1. Bell Work 11/28/12 Classify each triangle using angles and sides. 1)2) Write an equation for a line with the following: 3) parallel to:4) perpendicular to: y = 3x – 4; y-int at 5 y = -1/2x + 4 through (2, 1)

2. Outcomes I will be able to: 1) Identify congruent figures and their corresponding parts 2) Prove that two triangles are congruent 3) Write a congruence statement

3. Congruence What does it mean for two figures to be congruent? Congruence Investigation: 1) Open Geometry Pad 2) Plot each triangle 3) Find the measure of the angles and sides 4) Determine if the triangles are congruent 5) Decide what it means for figures to be congruent

4. Congruent Figures Two figures are congruent if they have the exact same size and shape The corresponding parts of congruent triangles are always congruent. So,

5. Congruence Statement Congruence Statement: A symbolic statement in which we write what figures are congruent. ***Be sure corresponding parts line up!!!

6. Congruent Figures Example 1a

7. Congruent Figures Example 1b Circle the figures that look congruent

8. Congruent Figures Example 2 Remember, corresponding parts must be congruent!!!

9. Congruent Figures Example 3 What do we know about angle A and angle D? So, how can we solve for x? 5x + 2 = 87 5x = 85 x = 17 What do we know about angle B and E? How can we solve for y? 87 + 42 + 3y = 180 3y = 51 y = 17

10. Third Angles Theorem If two angles of one triangle are congruent to two angles in another triangle, then the third angles are congruent. Angle A = 57 Angle B = 90 Angle C = x Angle D 57 Angle E = 90 Angle F = 33 Without doing any math, how can we find C? x = 33

11. Third Angles Example 1 What do we know about M and T? They are congruent How can we find x? 55 + 65 + 2x + 30 = 180 2x = 30 x = 15

12. Quiz Friday Quiz will cover: 1) Writing equations of parallel and perpendicular lines 2) Determining if two lines are parallel 3) Solving for variables in parallel lines 4) Classifying triangles

13. White Board Quiz Review 1) Find the variables X = 12 Y = 11

14. White Board Quiz Review 2) Write an equation of the line parallel to: y = 1/4x – 5 with a y-intercept of -11 y = 1/4x -11

15. White Board Quiz Review 3) Write an equation of the line perpendicular to: y = 1/3x + 4 through (-1, 5) (y – 5) = -3(x + 1) or y = -3x + 2

16. White Board Quiz Review 4) Are the lines parallel? Explain why/why not Yes, corresponding angles are congruent

17. White Board Quiz Review 5) Are the lines parallel? Explain why/why not. No, same side interior angles are congruent. They should add to 180°.

18. White Board Quiz Review 6) Write the equation of the line parallel to: y = 1/5x + 10 through (0, -5) (y + 5) = 1/5(x – 0) or y = 1/5x - 5

19. White Board Quiz Review 7) Are the lines parallel? Explain why/why not. No, same side interior angles do not add to 180°

20. White Board Quiz Review 8) Classify the following triangle using its sides and angles Acute Scalene Triangle

21. White Board Quiz Review 9) Classify the following triangle using its sides and angles. Right Scalene Triangle

22. White Board Quiz Review 10) Classify the following triangle using its sides and angles Equiangular equilateral triangle Could also be classified as isosceles or acute

23. Exit Quiz