Circles Circles Circles
Here at this website you'll get to know all about circles. What a circles is and many more things about circles and how to find the area.
What is a circle?
A circle is a flat round shape that has no corners.
Now for more information on a circle.
What is circumference?
Circumference is the distance around a circle.
How do you find circumference?
Well first of course you have to use the formula D x Pi = C. D stands for diameter. Pi is equal to 3.14 and C of course stands for circumference. Now, if you don't know the diameter you can use the radius. Here's the formula for using the radius to find it -> R x 2 x Pi = C.
What is diameter?
Diameter is a straight line that goes through the circle as you can see above.It splits the circle into two.
What is Pi?
Pi stands for 3.14, 3.14 and a whole bunch of other number.
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| Pi as in decimal |
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| Pi symbol |
What is radius?
Radius is a line starting from the circle to the center of the circle. In other words radius is half of diameter that is why we multiply it by 2.
Time for some examples
Lets say the radius of a circle is 4in. Well we have to find the circumference. How do we do it?!? I know how! By using the formula R x 2 x Pi. Well now lets put our numbers into the formula. R = 4in. Pi = 3.14. 4in x 2 x 3.14 = 25.12in. That was pretty easy lets do another one.
The diameter of a circle is 17cm. The formula is D x Pi. 17cm x 3.14 =53.38cm. Now that was too easy. One more.
We now know the circumference. The circumference is 26in. Now we have the formula D x Pi = C. Now we have to do the opposite of multiplying cause we are now working backwards to find the diameter. So what you do is you do 26in divided by 3.14 to get 8.28in as the diameter. I had to round. To find the radius you do the same thing, work backwards. So the formula is R x 2 x Pi. You do 26in divided by 3.14 which equals 8.28in then find the square root of 8.28in to get R.
