1 / 97

7-5

7-5. Triangles. Course 1. Warm Up. Problem of the Day. Lesson Presentation. Warm Up 1. What are two angles whose sum is 90°? 2. What are two angles whose sum is 180°? 3. A part of a line between two points is called a _________.

shanna
Download Presentation

7-5

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. 7-5 Triangles Course 1 Warm Up Problem of the Day Lesson Presentation

  2. Warm Up 1.What are two angles whose sum is 90°? 2. What are two angles whose sum is 180°? 3. A part of a line between two points is called a _________. 4. Two lines that intersect at 90° are ______________. complementary angles supplementary angles segment perpendicular

  3. Problem of the Day Find the total number of shaded triangles in each figure. 3 6 10

  4. Problem of the Day Find the total number of Total triangles in each figure. 5 13 24

  5. Learn to classify triangles and solve problems involving angle and side measures of triangles.

  6. Insert Lesson Title Here Vocabulary acute triangle obtuse triangle right triangle scalene triangle isosceles triangle equilateral triangle

  7. A triangle is a closed figure with three line segments and three angles. Triangles can be classified by the measures of their angles. An acute triangle has only acute angles. An obtuse triangle has one obtuse angle. A right triangle has one right angle. Acute triangle Obtuse triangle Right triangle

  8. To decide whether a triangle is acute, obtuse, or right, you need to know the measures of its angles. The sum of the measures of the angles in any triangle is 180°. You can see this if you tear the corners from a triangle and arrange them around a point on a line. By knowing the sum of the measures of the angles in a triangle, you can find unknown angle measures.

  9. Sara designed this triangular trophy. The measure of E is 38°, and the measure of F is 52°. Classify the triangle. To classify the triangle, find the measure of D on the trophy. m D = 180° – (38° + 52°) m D = 180° – 90° m D = 90° Additional Example 1: Application E D F Subtract the sum of the known angle measures from 180° So the measure of D is 90°. Because DEF has one right angle, the trophy is a right triangle.

  10. Sara designed this triangular trophy. The measure of E is 22°, and the measure of F is 22°. Classify the triangle. To classify the triangle, find the measure of D on the trophy. m D = 180° – (22° + 22°) m D = 180° – 44° m D = 136° Try This: Example 1 E D F Subtract the sum of the known angle measures from 180° So the measure of D is 136°. Because DEF has one obtuse angle, the trophy is an obtuse triangle.

  11. You can use what you know about vertical, adjacent, complementary, and supplementary angles to find the measures of missing angles. Let's Review First..

  12. Take two pencils (or pens) and have them intersect them in front of you like this…

  13. Finger Dance(Geometry)

  14. Finger Dance(Geometry) Adjacent Angles

  15. Finger Dance(Geometry) Vertical Angles

  16. Finger Dance(Geometry) Supplementary Angles

  17. Finger Dance(Geometry) Vertical Angles

  18. Finger Dance(Geometry) Supplementary Angles

  19. Finger Dance(Geometry) Adjacent Angles

  20. Finger Dance(Geometry) Adjacent Angles

  21. Finger Dance(Geometry) Supplementary Angles

  22. Finger Dance(Geometry) Vertical Angles

  23. Finger Dance(Geometry) Adjacent Angles

  24. Finger Dance(Geometry) Vertical Angles

  25. Finger Dance(Geometry) Vertical Angles

  26. Finger Dance(Geometry) Supplementary Angles

  27. Finger Dance(Geometry) Vertical Angles

  28. Finger Dance(Geometry) Vertical Angles

  29. Finger Dance(Geometry) Supplementary Angles

  30. Finger Dance(Geometry) Supplementary Angles

  31. Finger Dance(Geometry) Supplementary Angles

  32. Finger Dance(Geometry) Supplementary Angles

  33. For today’s warm-up, take out your list of vocabulary words, and TURN THEM OVER SO YOU CAN’T SEE THEM. Then, answer these three questions alone! • What are complementary angles? • What are supplementary angles? • What is the sum of all the angle measurements in a triangle?

  34. Supplementary Angles

  35. 50 ?

  36. Get a Partner and see if you can make Complimentary angles with your hands/arms…

  37. Find Complimentary Angles

  38. Find Complimentary Angles

  39. Find Complimentary Angles

  40. M N 160° 20° 20° R 160° Q P Do you remember this? When angles have the same measure, they are said to be congruent. Vertical angles are formed opposite each other when two lines intersect. Vertical angles have the same measure, so they are always congruent.

  41. M N 160° 20° 20° R 160° Q P Adjacent angles are side by side and have a common vertex and ray. Adjacent angles may or may not be congruent. REVIEW

  42. Identify the type of each angle pair shown. A. 5 6 They are vertical angles. REVIEW

  43. 7 and 8 are side by side and have a common vertex and ray. Identify the type of each angle pair shown. B. 7 8 They are adjacent angles. REVIEW

  44. 3 and 4 are side by side and have a common vertex and ray. Identify the type of each angle pair shown. A. 3 4 They are adjacent angles. REVIEW

  45. 7 and 8 are opposite each other and are formed by two intersecting lines. Identify the type of each angle pair shown. B. REVIEW 7 8 They are vertical angles.

  46. 65° + 25° = 90° LMN and NMP are complementary. L N 65° 25° M P Complementary angles are two angles whose measures have a sum of 90°. REVIEW

  47. 65° + 115° = 180° GHK and KHJ are supplementary. K 65° 115° G J H Supplementary angles are two angles whose measures have a sum of 180°. REVIEW

More Related