6th Grade Replacement Lesson - SVUSD

Lesson 5 - Circles

Circles

Vocabulary:

circle	diameter	radius
circumference	chord	pi

 

Web Resources:

Ask Dr. Math: About Pi
What is pi (π)? Who first used pi? How do you find its value? What is it for? How many digits is it?
A very brief history of pi

Circle Formulas: Area and Perimeter
I get confused with the different formulas, such as π•r² or π•d (Pi times radius squared or Pi times diameter). I don't remember which formula goes to which problem.

Circumference of A Circle
Calculating the circumference or perimeter of a circle has just gotten easier. You are given the formula for finding the circumference, then you can practice. An interactive site with links to games, lesson plans, and other math related activities.

Video Resources:

  Circles: An Introduction

  Circumference & Pi

  Area

Find the circumference of the following circles. Use 3.14 for pi (π).

 

Diameter = 5 cm a. 15.7 cm b. 31.4 cm c. 7.85 cm d. 78.5 cm

 

Diameter = 10 cm a. 314 cm b. 15.7 cm c. 31.4 cm d. 62.8 cm

 

Radius = 5 cm a. 15.7 cm b. 31.4 cm c. 78.5 cm d. 19.625 cm

Find the area of the following circles. Use 3.14 for pi (π).

 

radius = 10 cm a. 78.5 cm b. 314 cm c. 62.8 cm d. 31.4 cm

 

Diameter = 2 cm a. 6.28 cm b. 12.56 cm c. 4 cm d. 3.14 cm

 

 

 

 

 

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