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Unit #1, Concept #3 Angles and their Measurements. What are angles and how are they classified? How are the measures of angles used to determine their congruency? What is angle addition and how is it used?. Bell Ringer. With your partner…
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Unit #1, Concept #3Angles and their Measurements • What are angles and how are they classified? • How are the measures of angles used to determine their congruency? • What is angle addition and how is it used? Free Template from www.brainybetty.com
Bell Ringer With your partner… Come up with a list of some things that you remember about angles. Free Template from www.brainybetty.com
An angle ( ) • Is formed by two rays with the same endpoint. • The two rays are the sides of the angles. The endpoint is called the vertex of the angle Free Template from www.brainybetty.com
Naming Angles • 1 • Naming Angles C B A Free Template from www.brainybetty.com
Postulate 1 – 7Protractor Postulate • OA is paired with 0 and OB is paired with 180. • If OC is paired with x and OD is paired with y, then m<COD = |x – y|. D C y x A B Free Template from www.brainybetty.com
Find the measure of BOD D C A B Free Template from www.brainybetty.com
Find the measure of AOD D C A B Free Template from www.brainybetty.com
Types of Angles • Acute angles - an angle whose measure is between 0º and 90º. • Right angle - an angle whose measure is 90º. • Obtuse angle - an angle whose measure is between 90º and 180º. • Straight angle - an angle whose measure is 180º Free Template from www.brainybetty.com
Classify each angle AOY • as right, acute, obtuse or straight. Y X Z A B Free Template from www.brainybetty.com
Classify each angle BOY • as right, acute, obtuse or straight. Y X Z A B Free Template from www.brainybetty.com
Classify each angle BOA • as right, acute, obtuse or straight. Y X Z A B Free Template from www.brainybetty.com
Classify each angle XOZ • as right, acute, obtuse or straight. Y X Z A B Free Template from www.brainybetty.com
Find the measure of the followingAOX, XOY, YOZ, XOZ, YOB Y X Z A B Free Template from www.brainybetty.com
Let’s Get it Started • What did the segment addition postulate state? Free Template from www.brainybetty.com
Postulate 1 – 8 Angle Addition Postulate • If point B lies in the interior of AOC, then • m AOB + m BOC = m AOC. • C • B • O • A Free Template from www.brainybetty.com
Using the Angle Addition Postulate • m AOB = 54 • m AOC = 76 Find m BOC. C B O A Free Template from www.brainybetty.com
Using the Angle Addition Postulate • m COB = 2x + 6 • m AOB = 5x – 11 and m AOC =79 C B O find x A Free Template from www.brainybetty.com
Using the Angle Addition Postulate • Find the measure of angle 1 153° 1 Free Template from www.brainybetty.com
Using the Angle Addition Postulate • Find the value of x. (3x + 5)° (9x + 7)° Free Template from www.brainybetty.com
Congruent Angles • Are angles with the same measure. 1 2 Free Template from www.brainybetty.com
What can you deduce from this diagram? • A D • B E • C Free Template from www.brainybetty.com
What can you deduce from this diagram? • A D • B E • C Free Template from www.brainybetty.com
Journal Entry • What are angles and how are they classified? • 2. How are the measures of angles used to determine their congruency? • 3. What is angle addition and how is it used? Free Template from www.brainybetty.com
Classwork/Homework • Page 30 – 32 • # 17 – 23 odd, 24 – 28 all, 47, 48, 56-67, 70, 75 Free Template from www.brainybetty.com
Unit #1, Concept #3Angles and their Measurements • What are angles and how are they classified? • How are the measures of angles used to determine their congruency? • What is angle addition and how is it used? Free Template from www.brainybetty.com