1. Lesson 9

1.3. Explore 2

Module 2: Lesson 9

Module 2: Logic and Geometry

 

Self-Check 1

 


textbook
  1. Complete “Check Your Understanding” questions 1 and 2 on page 90 of your textbook. Answer

  2. Complete “Practising” question 6 on page 85 of your textbook. Answer

Now that you have proven that the sum of the interior angles in a triangle is always 180°, you can use this relationship (and other relationships that you already know) to determine

  • unknown angles measures
  • relationships between other angles
m20_2_tipbar_4.jpg

The symbol ~ represents similar to. When two triangles are similar, they are the same shape (i.e., the angles are the same) but are different sizes.

 

This is an image of two similar triangles.