1 / 16

2.4 – Vertical Angles

2.4 – Vertical Angles. Homework #5 Objectives #9, #10. Activity 2.4 – Angles and Intersecting Lines. On a piece of paper, draw line l using the straightedge of your protractor. Label two points A and B towards the end of the line. Activity 2.4 – Angles and Intersecting Lines.

efia
Download Presentation

2.4 – Vertical Angles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. 2.4 – Vertical Angles Homework #5 Objectives #9, #10

  2. Activity 2.4 – Angles and Intersecting Lines • On a piece of paper, draw line l using the straightedge of your protractor. Label two points A and B towards the end of the line.

  3. Activity 2.4 – Angles and Intersecting Lines • Draw line m so that it intersects line l. Label the point of intersection E. Label the points C and D towards the ends of line m.

  4. Activity 2.4 – Angles and Intersecting Lines • Use the protractor to measure (and record) the four angles formed by the intersecting lines.

  5. Activity 2.4 – Angles and Intersecting Lines • What do you notice about the nonadjacent angles you measured? • Find the sum of the measures of any two adjacent angles you measured. What do you notice?

  6. Defining Vertical Angles • Two angles are vertical angles if they are not adjacent and their sides are formed by two intersecting lines.

  7. Defining Linear Pair • Two adjacent angles are a linear pair if their non-common sides are on the same line.

  8. Example 1 Determine whether the labeled angles are vertical angles, a linear pair,or neither. SOLUTION Identify Vertical Angles and Linear Pairs b. c. a. a. 1 and2 are a linear pair because they are adjacent and their noncommon sides are on the same line. b. 3 and4 are neither vertical angles nor a linear pair. c. 5 and6are vertical angles because they are not adjacent and their sides are formed by two intersecting lines.

  9. Linear Pair Postulate

  10. Example 2 Find the measure of RSU. SOLUTION RSU andUST are a linear pair. By the Linear Pair Postulate, they are supplementary. To findmRSU,subtract mUST from180°. mRSU =180°– mUST = 180°–62° = 118° Use the Linear Pair Postulate

  11. Vertical Angle Theorem

  12. Example 3 Find the measure of CED. SOLUTION AEBandCED are vertical angles. By the Vertical Angles Theorem,CED AEB,so mCED = mAEB = 50°. Use the Vertical Angles Theorem

  13. Example 4 Findm1, m2,andm3. SOLUTION Find Angle Measures m2 = 35° Vertical Angles Theorem m1 = 180° – 35° = 145° LinearPairPostulate m3 = m1= 145° Vertical Angles Theorem

  14. Checkpoint Findm1, m2,andm3. Find Angle Measures 1. m1 = 152°; m2 = 28°;m3 = 152° ANSWER 2. m1 = 56°; m2 = 124°;m3 = 56° ANSWER 3. m1 = 113°; m2 = 67°;m3 = 113° ANSWER

  15. Example 5 SOLUTION Because the two expressions are measures of vertical angles, you can write the following equation. –2y = Divide each side by –2. –2 Use Algebra with Vertical Angles Find the value of y. (4y– 42)° = 2y° Vertical Angles Theorem 4y– 42 – 4y= 2y – 4y Subtract 4y from each side. –42 = –2y Simplify. –42 21 = y –2 Simplify.

  16. Checkpoint Use Algebra with Angle Measures Find the value of the variable. 4. ANSWER 43 5. ANSWER 16 6. ANSWER 5

More Related