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Do Now 3/15/12

Do Now 3/15/12. Take out HW from last night. Text p. 312, #1-16 all, 21 Copy HW in your planner. Text p. 318, #10-23 all, 27 & 28 In your journal, describe how to use a protractor. Use step-by-step instructions on how to measure an angle. 1) Q, R, S 2) 3) plane QRS 4) 5) 6)

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Do Now 3/15/12

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  1. Do Now 3/15/12 • Take out HW from last night. • Text p. 312, #1-16 all, 21 • Copy HW in your planner. • Text p. 318, #10-23 all, 27 & 28 • In your journal, describe how to use a protractor. Use step-by-step instructions on how to measure an angle.

  2. 1) Q, R, S 2) 3) plane QRS 4) 5) 6) 7) D, E, F 8) 9) plane DEF 10) 11) 12) 13) Plane ABC contains points A, B, C; lines AB & BC; line segments AB, AC, & BC; rays AB, BA, BC, CB, & CA. Plane ACD contains points A, C, D; line segments AC, AD, & CD; and ray CA Homework Text p. 312, #1-16 all, 21

  3. 14) 6; 15) answer vary 16) 21) C Homework Text p. 312, #1-16 all, 21

  4. Objective • SWBAT identify angles and angle pairs

  5. Section 8.2 “Classifying Angles” Angle two rays with a common endpoint. D Sides C Vertex E

  6. Naming Angles • The following angle can be named in three ways: B C A Vertex

  7. Types of Angles • Right angle = 90 degrees • Acute angle = less than 90 degrees • Obtuse angle = more than 90 degrees • Straight angle = exactly 180 degrees

  8. The MEASURE of is written as . • APROTRACTORcan be used to approximate the measure of an angle.

  9. Using a Protractor • Find = 130° A C B

  10. Using a Protractor • Find = 70° A C B

  11. What is the measure of a straight line (in degrees)? 180° A C B

  12. Supplementary Angles When two angles form a straight line, the sum of their measures is 180° D 180° 150° 30° A C E

  13. Complementary Angles When two angles form a right angle, the sum of their measures is 90° W 90° 64° Z 26° X Y

  14. P Q O N R M Use the diagram to tell whether the angles are complementary, supplementary, or neither. OMP and PMQ 30° 60° OMP = 60° and PMQ = 30° and 30°+60° = 90° therefore, they are complementary.

  15. P Q O N R M Use the diagram to tell whether the angles are complementary, supplementary, or neither. NMO and OMR 165° 15° NMO = 15° and OMR= 165° and 15°+165° = 180° therefore, they are supplementary.

  16. Use the diagram to tell whether the angles are complementary, supplementary, or neither. D E C F B A BAC and EAF 35° 35° BAC = 35° and EAF= 35° and 35°+35° = 70° therefore, they are neither.

  17. Finding Angle Measures Angles A and B are complementary. If mA is 56°, what is the mB? Since A and B are complementary, mA + mB = 90°. mA + mB = 90° 56° + mB = 90° Substitute 56° for mA. Subtract 56° from both sides. – 56° – 56° mB = 34° The measure of B = 34°.

  18. Finding Angle Measures Angles P and Q are supplementary. If mP is 32°, what is the mQ? Since P and Q are supplementary, mP + mQ = 180°. mP + mQ = 180° 32° + mQ = 180° Substitute 32° for mP. Subtract 32° from both sides.. – 32°– 32° mQ = 148° The measure of Q = 148°.

  19. Homework • Text p. 318, #10-23 all, 27 & 28

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