1 / 32

Angle Measurements

Angle Measurements. Lesson 1.2 – Poolroom Math. Homework: 1.2/ 2-40 evens. Geometry Honors Homework: 1.2/ 2-40 evens, 41-45, 48. Protractor. A device used to measure angles. Measuring, calculating and drawing angles. Our learning objectives today To use a protractor to:

beverly-leblanc
Download Presentation

Angle Measurements

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. Angle Measurements Lesson 1.2 – Poolroom Math Homework: 1.2/ 2-40 evens Geometry Honors Homework: 1.2/ 2-40 evens, 41-45, 48

  2. Protractor A device used to measure angles.

  3. Measuring, calculating and drawing angles... Our learning objectives today To use a protractor to: • measure acute and obtuse angles to the nearest degree. • draw acute and obtuse angles to the nearest degree. To calculate angles on a straight line.

  4. We use protractors to help us measure angles These are standard protractors.

  5. When we use a protractor, we need to line it up correctly with the angle. You need to make sure the protractor is lined up correctly. Are these protractors ready to measure the angle?

  6. No!! The angles must be lined up properly. Look for the upside down ‘T’ in the middle of the straight line on your protractor. In this protractor look for the hole in the center. These spots need to be exactly on the vertex of your angle.

  7. We also need to remember to line up the base One side of the angle must be lined up with the base of the protractor. It doesn’t matter which side.

  8. What is the angle measure? This angle measures 35°. The side of the angle passes over 2 measurements: 145° and 35°. Which one is correct?? This is an acute angle. Therefore, the measurement should be between 0 & 90°.

  9. Full Revolution A revolution is an angle that equals exactly 360º.

  10. Reflex Angle A reflex angle is greater than 180º and less than 360º. It represents the largest amount of rotation.

  11. Measuring Reflex Angles Now, we will use a protractor to measure the reflex angle PQR. To measure the reflex angle PQR, 1. Measure the smaller angle PQR. 2. Subtract from 360°.

  12. Angle Bisector The bisector of an angle, also called the angle bisector is the ray, line or line segment that divides the angle into two equal parts(marked by slash marks). . D

  13. Adjacent Angles <ADB + <ADC = 180° <ADB and <ADC are adjacent angles

  14. Complementary Angles Two angles are called complementary angles if the sum of their degree measurements equals 90 degrees. Example: These two angles are complementary. Their sum is 90˚. 58° + 32° = 90°

  15. Complementary Angles These two angles can be "pasted" together to form a right angle! Adjacent Complementary Angles.

  16. Supplementary Angles Two angles are called supplementary angles if the sum of their degree measurements equals 180 degrees. Example: These two angles are supplementary. The sum of their measures is 180˚ 139° +41° = 180 °

  17. Linear Pair of Angles Special Supplementary Angles Two angles that share a vertex and a side to form a line.

  18. Vertical Angles Opposite angles formed by intersecting lines .  For any two lines that meet, such as in the diagram below, angle AEB and angle DEC are called vertical angles. Angle BEC and angle AED are also vertical angles. Vertical angles are congruent - have the same degree measurement. 110 70 70 110

  19. Angles Around a Point Angles around a point will always add up to 360° The angles above all add to 360° 53° + 80° + 140° + 87° = 360°

  20. Example: What is angle “C"? We can find an unknown angle using this sum. To find the measure of angle C find the sum of the known angles and subtract that from 360° . Sum of known angles = 110° + 75° + 50°  + 63° =298° m< C = 360° − 298° m< C = 62°

  21. Pool Room Math Incoming angles = outgoing angles

  22. Will the 4 ball land in the pocket??

  23. Which path will the cue ball follow?

  24. Will the blue ball land in a pocket?

  25. More drawings Find the measure of all the angles with vertex C F E 20 70 90 Box in the corner indicates a right angle. D G C 70 90 J 20 H

  26. Final DrawingFind the measure of all the angles with vertex G. B C 68 60 52 A G D 52 60 68 F E

More Related