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In this video, let's discuss about the circumference of a circle and the area of a circle.

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All right.

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We have seen that the circumference of a circle is the same thing as the perimeter of a polygon, right?

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It's the distance around a circular region.

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So the circumference is the distance around the circular region or it's the measure of the border.

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Right over here you have a circle.

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Now, the circumference would be this distance.

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Right, so this distance is the circumference now let this be the center of this circle.

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Now, if you draw a line through the center, we get a diameter, right?

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All right.

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Let's keep that over here.

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Now, let me call the circumference as see, OK?

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Now, if you take any circle and if you divide see with their diameter, if you divide the circumference

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of this circle with the diameter of the circle, you will get a unique ratio.

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It will be a constant or any circle.

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And that constant is what we have defined us by.

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Now, the value of PI is approximately taken as twenty two by seven or three point one four.

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Now in actual case, by is an irrational number.

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So it's it's an unending number.

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The decimals will never and it will keep on going like that.

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But in problems we approximate it to twenty two by seven or three point one for now using this part

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C by two R gives you pi.

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Right.

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What is the radius.

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Twice the rate is that the diameter now C by two R is equal to PI.

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Therefore using this concept we can find that the circumference of a circle is equal to two pi are all

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right now, having established how to find the circumference of a circle.

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Let's move on and find how to find the area of a circle.

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Over here I have a circle and let's see by the center of the circle and R is the radius of this circle.

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Now if you want to find the area of the circle that is this region over here, then all you need to

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do is you need to multiply by with the square of the radius.

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So the area of a circle is given by a single payer square.

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So if you are given that the radius is equal to seven centimeter and you want to find the area of this

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circle, what you need to do, you can approximate PI to twenty two by seven and radius square will

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be seven to seven.

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And that gives you the answer as 22 into seven centimeter square.