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Pre-AP Bellwork. 6) Claire draws an angle that measures 56. Justin draws a congruent angle. Justin says his angle is obtuse. Is he correct? Why or why not?. Pre-AP Bellwork. 7) ∠MLN and ∠JLK are complementary, m∠MLN = 7x − 1, and m∠JLK = 4x + 3. a. Solve for x. b. Find m∠MLN and m∠JKL.
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Pre-AP Bellwork 6) Claire draws an angle that measures 56. Justin draws a congruent angle. Justin says his angle is obtuse. Is he correct? Why or why not?
Pre-AP Bellwork 7) ∠MLN and ∠JLK are complementary, m∠MLN = 7x − 1, and m∠JLK = 4x + 3. a. Solve for x. b. Find m∠MLN and m∠JKL. c. Show how you can check your answer.
Pre-AP Bellwork 8)Describe all the situations in which the following statements are true. a. Two vertical angles are also complementary. b. A linear pair is also supplementary. c. Two supplementary angles are also a linear pair. d. Two vertical angles are also a linear pair.
Pre-AP Bellwork Find the measure of each angle in the angle pair described. 9) The measure of one angle is 5 times the measure of its complement. 10) The measure of an angle is 30 less than twice its supplement.
Adjacent angles- two coplanar angles with a common side, a common vertex, and no common interior points
Which angles are adjacent? 1& 2, 2& 3, 3& 4, 4& 1 Then what do we call 1& 3? Vertical Angles – 2 angles that share a common vertex & whose sides form 2 pairs of opposite rays. 1& 3, 2& 4 2 1 3 4
Linear Pair (of angles) • 2 adjacent angles whose non-common sides are opposite rays. 1 2
Example 2 • Vertical angles? 1 & 4 • Adjacent angles? 1& 2, 2& 3, 3& 4, 4& 5, 5& 1 • Linear pair? 5& 4, 1& 5 • Adjacent angles not a linear pair? 1& 2, 2& 3, 3& 4 1 3 5 4
Important Facts • Vertical Angles are congruent. • The sum of the measures of the angles in a linear pair is 180o.
Example: • If m 5=130o, find m 3 m 6 m 4 4 =130o =50o =50o 5 3 6
A Example: E 3x+5o y+20o B x+15o 4y-15o D • Find x,y m ABE m ABD m DBC m EBC C x=40 y=35 mABE=125o m ABD=55o m DBC=125o m EBC=55o
Complementary Angles • 2 angles whose sum is 90o 35o 1 2 55o A 1 & 2 are complementary A & B are complementary B
Supplementary Angles • 2 angles whose sum is 180o 1 & 2 are supplementary. X & Y are supplementary. 1 2 130o 50o X Y
Ex: A & B are supplementary. m A is 5 times m B. Find m A & m B. m A + m B = 180o m A = 5(m B) Now substitute! 5(m B) + m B = 180o 6(m B)=180o m B=30o m A=150o