1. Flashcards Pick a partner Get a set of flashcards Work on identifying angles You will have 10 minutes Go

3. Vocabulary Postulate – a notion that makes so much sense we don’t even have to prove it. ♥ a circle has 360° ♥ a line segment only has one midpoint ♥through any two points, there is exactly one line Theorem – a rule. It used to be an idea but it was PROVEN to be true. ♥Pythagorean Theorem: a 2 + b 2 = c 2, if c is the hypotenuse ♥Right Angle Congruence Theorem: All right angles are congruent. See proof.proof

4. Triangle Sum Theorem & Exterior Angle Theorem

5. Triangle Sum Theorem The sum of the angle measures in a triangle equal 180° 3 2 1 m<1 + m<2 + m<3 = 180°

6. Exterior Angle Theorem (your new best friend) The measure of an exterior angle in a triangle is the sum of the measures of the 2 remote interior angles 3 2 1 4 exterior angle remote interior angles m<4 = m<1 + m<2

7. an example with numbers x 82° 30°y find x & y x = 68° y = 112° 40x10x 30xfind all the angle measures y

8. White boards Please get: whiteboard marker eraser

9. 3x + 20 5x Find x Find the measure of each angle 3x + 20 + 5x = 180 8x = 160 X = 20 100° and 80° X - 1 2X - 3 X 2X Perimeter = 76 Find x and the length of each side 8x – 4 = 76 8x = 80 X = 10 20 9 10 17 Check your work: does 10 + 20 + 9 + 20 + 17 Equal 76?

10. 3x - 2 Find x and then find the measure of each angle 5x - 14 Find x and then find the length of each side. 3x – 2 = 5x – 14 12 = 2x 6 = x 16 units 3x + 20 5x 3x + 20 = 5x 20 = 2x X = 10 50° 80°

11. Find all the missing angles 75° 85° 75° 95° 105° 85° 75° 105° 85° 95° 85°

12. Find all the missing angles 30° 110° 70° 80° 110° 70° 110° 80° 30° 80° 100°

13. Find the measure of angle x x 80° 40° 80 + 40 + x = 180 120 + x = 180 X = 60° Check your work. Does 80 + 40 + 60 equal 180? 96° X + 12° 2X° Find the measure of each angle 2x + x + 12 + 96 = 180 3x + 108 = 180 3x = 72 X = 24 48°, 36° and 96° Do they equal 180°?

14. Your assignment Pg 92 – 97; 38 - 42, 51, 55