Lesson 10-6 Pages 440-443

Similar Figures

What you will learn!

How to determine whether figures are similar and find a missing length in a pair

of similar figures.

Similar figuresSimilar figures

Indirect measurementIndirect measurement

What you really need to know!

Two figures are similar if corresponding angles are congruent and corresponding sides are proportional. The symbol ~ means is similar to.

C

5 4

3A

B810

6 FD

E∆ABC ~ ∆DEF

C

5 4

3A

B8

10

6 FD

E

Corresponding angles

A D

B E

C F

Corresponding sides

6

3

8

4

10

5

Link to Pre-Made Lesson

Example 1:

If ∆ABC ~ ∆DEF, find the length of DF.

n

11

5.4

3 5.493 n

5.16n

Example 2:

A rectangular picture window 12-feet long and 6-feet wide needs to be shortened to 9-feet in length to fit a redesigned wall. If the architect wants the new window to be similar to the old window, how wide will the new window be?

n

6

9

12 5412 n

5.4nft5.4

Page 442

Guided Practice

#’s 3-5

Pages 440-441 with someone at home and study

examples!

Read:

Homework: Page 442-443

#’s 6-15 all

#’s 18-27 all

Lesson Check 10-6

Page

588

Lesson 10-6

Study Guide and Review

Pages

462-464

#’s 6-22(Odd answers in back of book)

Prepare for Test!

Pages

465

#’s 3-13, 16