1 / 14

Chapter 1 Lesson 4

Chapter 1 Lesson 4. Objective: To find the length of segments and measures of angles. Postulate 1-5 Ruler Postulate. The distance between points A and B, written as AB, is the absolute value of the difference of the coordinates of A and B. X. Y. 0.

ross
Download Presentation

Chapter 1 Lesson 4

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. Chapter 1 Lesson 4 Objective: To find the length of segments and measures of angles.

  2. Postulate 1-5Ruler Postulate The distance between points A and B, written as AB, is the absolute value of the difference of the coordinates of A and B. X Y 0 Since x is at -2 and Y is at 4, we can say the distance from X to Y or Y to X is: -2 – 4 = 6 or 4 – (-2) = 6

  3. Measure the length of STto the nearest tenth of a centimeter. Align one mark of a metric ruler with S. Then estimate the coordinate of T. For example, if you align Swith 2, T appears to align with 5.4. ST=5.4 – 2 = 3.4 The length of STis about 3.4 centimeters. ANSWER EXAMPLE 1 Apply the Ruler Postulate SOLUTION Use Ruler Postulate.

  4. Postulate 1-6 Segment Addition Postulate If Q is between P and R, then PQ + QR = PR. If PQ +QR = PR, then Q is between P and R. 2x 4x + 6 R P Q PQ = 2x QR = 4x + 6 PR = 60 Use the Segment Addition Postulate find the measure of PQ and QR.

  5. Use the diagram to find GH. FH = FG+ GH 36 21+GH = 15 GH = EXAMPLE 2 Find a length SOLUTION Use the Segment Addition Postulate to write an equation. Then solve the equation to find GH. Segment Addition Postulate. Substitute 36 for FHand 21 for FG. Subtract 21 from each side.

  6. Angles Formed by 2 rays with the same endpoint Vertex of the Angle Symbol: [  ] Name it by: Its Vertex A A number 1 Or by 3 Points BAC Vertex has to be in the middle B 1 A C

  7. Ex.3: How many s can you find? Name them. 3 s ADB or BDA BDC or CDB ADC or CDA Notice D (the vertex) is always in the middle. Can’t use D But 1 or 2 could be added. B A 1 2 C D

  8. Classifying Angles by their Measures Acute  Right  Obtuse  x° x° x° x < 90° x = 90° x > 90° x° Straight  x = 180°

  9. Protractor Postulate • P (1 – 7) Let OA & OB be opposite rays in a plane, & all the rays with endpoint O that can be drawn on one side of AB can be paired with the real number from 0 to 180. C D A O B

  10. Angle Addition Postulate • If point B is in the interior of MAD, then mMAB + mBAD = mMAD B M D A

  11. If MAD is a straight , then mMAB + mBAD = mMAD = 180° B D M A

  12. Ex.4: Finding  measures • Find mTSW if • mRSW = 130° • mRST = 100° W T R S mRST + mTSW = mRSW 100 + mTSW = 130 mTSW = 30°

  13. Ex. 5  Addition Find x. mXYZ = 150 x 1 = 3x - 15 2 = 2x - 10 Z Y m1 + m2 = mXYZ (3x - 15) + (2x – 10) = 150 5x – 25 = 150 5x = 175 x = 35

  14. Assignment • Page 29-30 • #1-28 • #42-64 Even

More Related