1 / 11

Copy these into your Glossary

"It's okay to make mistakes. Mistakes are our teachers -- they help us to learn." John Bradshaw. Copy these into your Glossary. X. Y. Y. W. X. F. S. A. D. E. B. C. P. G. H. J. Acute.

orea
Download Presentation

Copy these into your Glossary

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. "It's okay to make mistakes. Mistakes are our teachers -- they help us to learn." John Bradshaw Copy these into your Glossary X Y Y W X F S A D E B C P G H J Acute

  2. Chapter 4.2 Angles of Triangles:Objective: Understand and apply the angle sum and exterior angle theorems. Check.4.11 Use the triangle inequality theorems (e.g., Exterior Angle Inequality Theorem, Hinge Theorem, SSS Inequality Theorem, Triangle Inequality Theorem) to solve problems. Check.4.12 Apply the Angle Sum Theorem for polygons to find interior and exterior angle measures given the number of sides, to find the number of sides given angle measures, and to solve contextual problems. Spi.4.11 Use basic theorems about similar and congruent triangles to solve problems.

  3. Angles of Triangle Cut out a triangle (1/2 size of a piece of paper) Label vertices A, B, and C (on front and back) Fold vertex B so it touches AC the fold line is parallel AC Fold A and C so they meet vertex B What do you notice about the sum of angles A, B and C? Tear of vertex A, and B Arrange A and B so they fill in the angle adjacent and supplementary to C. What do you notice about the relationshipA and B and the angle outside C?

  4. "It's okay to make mistakes. Mistakes are our teachers -- they help us to learn." John Bradshaw Demonstrated 2 Theorems X Y Y W X F S A D E B C P G H J Acute

  5. X Y 3 1 Angle Sum TheoremGiven ABC Prove: mA+mB+mC = 180 2 Statement Reasons Given Parallel Postulate Def of linear pair If 2 ’s form a linear pair, they are supplementary Def of supplementary ’s Angle Addition Postulate Substitution Alternate Interior Angle Theorem Def of congruent angles Substitution A • ABC • Line XY through A || CB • 1 and CAY form a linear pair • 1 and CAY are supplementary • m1+mCAY=180 • mCAY= m2+m3 • m1+m 2+m3=180 • 1 C, 3 B • m1=mC, m3=mB • mC+m 2+mB=180 B C

  6. Find the missing Angles m1 + 28 + 82 = 180 m1 + 110 = 180 m1 = 70 82 m1 = m2 vertical angles 28 1 2 m2 + m3 + 68 = 180 70+ m3 + 68 = 180 68 m3 + 138 = 180 3 m3 = 42

  7. Find the missing Angles m1 + 74 + 43 = 180 m1 + 117 = 180 m1 = 63 79 m1 = m2 vertical angles 43 2 1 74 3 m2 + m3 + 79 = 180 63 + m3 + 79 = 180 m3 + 142 = 180 m3 = 38

  8. 3 Find the angle measures 2 50 120 4 1 5 56 78 m1 = 50 + 78, exterior angle theorem m1 = 128 • m1 + m2 = 180, linear pair are supplemental • 128 + m2 = 180 • m2 = 52 • m2 + m3 = 120 exterior angle theorem • 52+ m3 = 120 • m3 = 68 • 120 + m4 = 180, linear pair are supplemental • m4 = 60 • m4 + 56 = m5 exterior angle theorem • 60+ 56 = m5 • 116= m5

  9. 38 Find the angle measures 32 4 3 1 5 2 64 41 29 m1 = 32 + 38 m1 = 70 • m1 + m2 = 180, linear pair are supplemental • m2 = 110 • m2 = m3 +64exterior angle theorem • m3= 110 – 64 = 46 • m3 + m4 +32 = 180 • 46 + m4 + 32 = 180 • m4 = 102 • m4 + m5 +41 = 180 • 102 + m5 +41 = 100 • 37= m5

  10. Right Triangle m1 = 90 – 27 m1 = 63 27 1

  11. Practice Assignment • Standard - page 248, 12 -32 Even • Honors - Page 189 24 – 44 Even

More Related