1. LINE AND ANGLE RELATIONSHIPS 10.2 Interior and Exterior Angles

2. Angle Sum of a Triangle Concept: The sum of the measure of the _________ angles of a triangle is equal to _______. Angle 1 + Angle 2 + Angle 3 = _______ Examples A)Find the value of x in the Antigua and Barbuda flag. x + ____ + ____ = 180 x + _____ = 180 B) In triangle ABC, if angle A = 72° and angle B = 74°, what is the measurement of angle C? Exterior Angles of a Triangle Concept: The measure of an __________ angle of a triangle is equal to the sum of the measures of its two remote __________ angles. Angle 4 is an _________ angle. Angle 1 and Angle 2 would be the _______________ angles. Angle ___ + Angle ___ = Angle ___ Something to think about… Angle 3 and Angle 4 make a straight angle. They must also equal _____. Examples A)Suppose m<4 = 135°. Find the measure of <1. Angle 4 is an exterior angle. Its two remote interior angles are <1 and <2 (the right angle). m<1 + m<2 = m<4 x + ___ = _____ 1 2 3 55° x° 1 2 3 4 13 4

5. TRIANGLE CARDS FILL IN THE INFORMATION The sum of the angles in a triangle is 180. a + b + c = 180

6. TRIANGLE UNKNOWNS ? XX X find x 180-90-45

7. 2x + 3x + 4x = 180 9x = 180 9 9 x = 20

10. ? What is the above angle measure? Lets keep this in mind

11. ? Triangle Angle Names Exterior Angle Remote Interior Angles FYI Another Name for Remote Interior Angles are: Non-adjacent Angles

12. TRIANGLE CARDS FILL IN THE INFORMATION The sum of the Remote Interior Angles equal the measure of the Exterior Angle. a + b = d

13. TRIANGLE UNKNOWNS ? ? 45 + 90 = ? ? ? + 57 = 120 ? + 57 = 120 - 57 -57 ? = 63

14. 2x + 3x = 105 5x = 105 5 5 x = 21

15. Day 1 – Integer operations, PEMDAS, evaluating 10.2 Interior and Exterior Angles find x: Number 13 on your Homework x x + 62 = 139

16. RECAP The sum of the angles in a triangle is 180. a + b + c = 180 The sum of the Remote Interior Angles equal the measure of the Exterior Angle. a + b = d

17. ? When figures get bigger, do the angles get bigger? SIMILARITY THEOREM A A’ Sides get bigger... If you had 2 triangles with the same angle measures, would the triangles be similar? 30 25 125 but ANGLES DON’T!

18. ? SIMILARITY THEOREM 25 125 SAME ANGLES SAME SHAPE! IF 2 angles are congruent ‘s are SIMILAR What’s the MINIMUM number of angles you need to know to determine if 2 triangles are similar???

19. Are These Triangles Similar?

20. Similarity Recap ‘s are SIMILAR