Circumference Of A Circle  by  Alice Akinyi

6

CIRCUMFERENCE

What is circumference?

It's the distance a round a circular object (circle)

 

A CIRCLE

  • Identify the circumference

Other examples include ;

(a) A ring

(b) A wheel 

 

A bicycle  wheel and A car wheel.

© Coin

  • Kenyan coin

( d) An Orange and lid
 
 
 
(e) Clock
 
  • Observe the seconds hand of 

 

 

6

DIAMETER

What is diameter? 
 
Its the distance around the circumference across the center of the circle
It divides the circle into two equal halves 
 
 
The relationship between diameter and circumference
 
 
  • Use a string to measure

Relationship between diameter and circumference

Fit the diameter around the Circumference

 

The length of the diameter fits the circumference 3 1/7 

RADIUS

What is radius ?
  • It's the distance from the center of the diameter to  the circumference
  • It divides the diameter into  two  equal halves

 

Two radius make one diameter

  • Identify the radius 

 

Relationship between the radius and the circumference

Circumference   =   2radius (2r) × pi

ACTIVITIES

Measure and record circumference and diameters of different objects and complete the table

Object

Circumference

Diameter

Radius

Circumference

____________

Diameter        = (C/D)

Shoe lid

       

Coin

       

Bottle top

       

Orange

       

Ball

       

Glass

       

 



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