1. 11.6 Similar Triangles & Proportions 33 22 11 Definitions Formulas & Examples Practice Problems

2. Key Concepts  The sum of the interior angles of any triangle is 180˚  a proportion is an equation stating two ratios are equivalent (i.e. 2/3 = 4/6)  to solve a proportion for a variable, we multiply the cross products 2

3. Key Concepts 3  is the symbol for a triangle  is the symbol for similar  is the symbol for an angle  the side of a triangle is named by using the two angle names it touches with a line segment symbol above

4. Key Concepts 4  Congruent (identical) angles will have the same identifying marks  is congruent to

5. Similar Triangles 5  Similar triangles are proportional:

6. Similar Triangles 6  Similar triangles have the same corresponding angle measures: 25˚ 70˚ 85˚

7. Example 7 Determine if the two triangles are similar 78˚ 51˚

8. Example 8 Find the missing measures 98˚ 51˚ 98˚ 47˚ 4 3 6 a b 16

9. Practice Problems  Page 619 Problems 11-24 Even due today Odd due next class 9