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Chapter 1. 1-4 Pair of Angles. Warm-up. 1. BD bisects ABC , m ABD = , and m DBC = ( y + 4)°. Find m ABC . 2. m WYZ = (2 x – 5)° and m XYW = (3 x + 10)°. Find the value of x. Warm-up answers.
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Chapter 1 1-4 Pair of Angles
Warm-up 1.BD bisects ABC, mABD = , and mDBC = (y + 4)°. Find mABC. 2.mWYZ= (2x – 5)° and mXYW= (3x + 10)°. Find the value of x.
Warm-up answers • 1.BD bisects ABC, mABD = , and mDBC = (y + 4)°. Find mABC. • Answer:32° • 2.mWYZ= (2x – 5)° and mXYW= (3x + 10)°. Find the value of x. • Answer: 35
Objectives • Students will be able to: • * Identify adjacent, vertical, complementary, and supplementary angles. • * Find measures of pairs of angles.
1-4 pair of angles • What is an angle? • Answer: an angle is a figure formed by two rays with a common endpoint of vertex. • What are some of the different types of angles you have heard?
1-4 pair of Angles • So today we are going to see different kinds of pair angles like • Linear pairs add up to 180
1-4 Pair of angles • You can find the complement of an angle that measures x° by subtracting its measure from 90°, or (90 – x)°. • You can find the supplement of an angle that measures x° by subtracting its measure from 180°, or (180 – x)°.
1-4 Pair of Angles • Another angle pair relationship exists between two angles whose sides form two pairs of opposite rays. Vertical anglesare two nonadjacent angles formed by two intersecting lines. 1and 3are vertical angles, as are 2and 4. • Vertical angles are congruent.
1-4 pair of Angles • Example #1 • Tell whether the following pair of angles are linear, adjacent , vertical or complementary. • From the Angle Pair relationship worksheet • Problem s 1, 2, 5 and 8 • Student Guide 3, 4, 6,7
1-4 Pair of Angles • Example #2 • From the angle pair worksheet problems 9,10,12 • Student guide 13,14 and 18
1-4 pair of angles • Example #3 • Angle pair worksheet Problem 19,20 Student guide 21 and 22
1-4 Pair of angles • Just Remember complementary add up to 90 and supplementary add up to 180. • Example #4 • Two angles are complementary. One angle is 4 times the other. The other angles is x+6. Find the two angles . • Answer: • Angle1+angle 2=90 • (x+6)+4(x+6)=90 • X+6+4x+24=90 • 5x+30=90 • 5x=60 • X=12 • Angle 1=18, Angle2=72
1-4 pair of angles • Example #5 • One angle is 5x+3 and its supplementary angle is 3times the other angle. Find x • Answer: • 5x+3+3(5x+3)=180 simplify • 5x+3+15x+9=180 combine like terms • 20x+12=180 solve for x • 20x=168 divide by 20 • X=8.4
1-4 pair of angles • Homework page 32 • Problems # 14, 18,19 ,26,29 • Finish the angle pair worksheet
Closure • Today we learned about the different pair angles like linear angles, adjacent angles, vertical angles. We also learned about complementary and supplementary angles. Tomorrow we are going to have a quiz and continue with 1-5 part 1.