- 226 Views
- Uploaded on
- Presentation posted in: General

Perimeter and Area of Similar Figures

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

7th Grade Math

Lesson Objective:

Students will find the perimeter and area of similar figures.

Perimeter and Area of Similar Figures

- How to find
- Add each side length of an object

- Similar Figures Rule
- P(New)= P(Original)• SF

- Scale Factor
- New/Original

- Two rectangles are similar. One has a length of 6 inches and a perimeter of 24 inches. The other has a length of 7 inches. What is the perimeter of this rectangle?

SF = 7/6

P = 24 • 7/6

P = 28 in

L

P

18 m

24 m

Q

R

M

N

P = 64 m

LMN is similar to PQR

P = 64 • 3/4

SF = 18/24 or 3/4

P = 48 m

- How to find
- Rectangle = bh
- Triangle = ½bh

- Similar Figures Rule
- A(New)= A(Original)• SF2

- Scale Factor
- New/Original

- The Eddingtons have a 5-foot by 8-foot porch on the front of their house. They are building a similar porch on the back with double the dimensions. Find the area of the back porch.

A = 40 • 22

SF = 2

A = 40 • 4

A = 160 ft2

- Malia is painting a mural on her bedroom wall. The image she is reproducing is 1/20 of her wall and has an area of 36 square inches. Find the area of the mural.

A = 36 • 202

SF = 20

A = 36 • 400

A = 14,400 in2

- A company wants to reproduce the size of its logo by one fourth to use on business cards. If the area of the original logo is 4 square inches, what is the area of the logo that will be used on the business cards?

A = 4 • (¼)2

SF = ¼

A = 4 • 1/16

A = 0.25 in2