Circle
Areas of plane figures
 
Deduce the formula for the area of a circle.
 

We can deduce the formula for the area of a circle from the area of a regular polygon.

Take the blue dot to the right and observe what happens.

- Find the similarities between the circle and a regular polygon.

- What is the circumference of the circle equivalent to?

- What is the radius of the circle equivalent to?

- Substitute these variables and simplify. Thus, you will get the formula for the area of a circle.
       
           
  Eduardo Barbero Corral
 
Spanish Ministry of Education , Social Afairs and Sport. Year 2007
 
 

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