Aim: How do we find the area of circles?

You can find areas of circles by using the formula which is going to be tought through this lesson.:)

Circle
What is the formula for the area of a circle?



Pii times the radius to the cube(square).

 Here is an exapmle:

A circle has a radius of 22. First you are going to ssquare the radius which will give you 484!!
After that you multiply by pii. Then you multiply by pii. You`re final product is 1,520.53.


What about if they give you the diameter and not the radius?
All you need to do is divide the diameter by 2 since the diameter is twice the size of the radius.


Here is an example,



You divide 38 cm by 2. Which will give you 19.
Then, you multiply by pii. Which will then give you a product of 59.69.

How about if they give you the circumference?
 First of all in order to find the circumference of a circle you need to multiply diameter times pii.
In order to find the area of a circle you need the radius. Therefore, you divide the product by two and you will get the radius. From there, you move on and multiply by pii.

Here is an example:



This circle has a diameter of 18 and when you multiply by pii you get 14.85. You divide the diameter by two which gives you 9. Nine cubed equals to 81. Then you multiply by pii and you get a product of 254.46.


                                                 Try it on your own!!

What is the area of of a circle which has a radius of 234 cm? Hmmmmmm?

All info. from my brain and pics. from google.com