Discovering Geometry Chapter 11

Lesson 1: 11.1

Lesson 2: 11.2

Lesson 3: 11.3

Lesson 4: 11.5

Lesson 5: 11.6

Lesson 6: 11.7

Lesson 7: REVIEW

Warm-Up

Proportion Practice

“What do you call it when you cut up your credit cards?”

Be prepared to show your work on the board.

Chapter 11: Similarity

In this section we will answer…

What does it mean for polygons to be similar?

How can I use similarity to help me solve problems?

CONGRUENT

Identical in shape and size

Identical in shape, not necessarily size

SIMILAR

Definition of Similar:

Two polygons are similar if:

corresponding angles are congruent and

corresponding sides are proportional.

Symbol: ~

Example

Quad CORN ~ Quad PEAS

Which angles are congruent?

Which sides are proportional?

Dilation

When a figure is enlarged or reduced

Dilation Similarity Conjecture

If one polygon is a dilated image of another polygon, then the polygons are similar.

32

In this section we will answer…

Do I have to prove ALL corresponding angles congruent and ALL corresponding sides proportional to prove similarity?

Which shortcuts actually work everytime?

SKIP FOR NOW

AA Similarity Conjecture

If two angles of one triangle are congruent to two angles of another triangle, then the two triangles are similar.

If not, write “can’t be proven”.

If yes, write a similarity statement and solve for the missing pieces.

SSS Similarity Conjecture

If the three sides of one triangle are proportional to the three sides of another triangle, then the two triangles are similar.

SAS Similarity Conjecture

If two sides of one triangle are proportional to two sides of another triangle, and the included angles are congruent, then the two triangles are similar.

At the Beginning of Your Notes…

Almost Finished…

Clear Your Calculator and Turn It Off

2nd + 7 1 2 then 2nd On

Take out your agenda – copy down due dates

Quizzes

Tests

Homework

11.1 Similar Polygons

11.2 Similar Triangles

Do NOT pack up until you are told to do so!