i need help with circumfrence.. i dont understand it...?

Answer 1

Hi
Not sure what you don't understand but I'll take a shot at it.

The concept of circumference can be illustrated by looking at the wheel of a car.

Area is the whole wheel and tire together as if you laid it flat on the driveway and drew a line around it The part inside such a circle would be the area.

Circumference is just the tread around the outside of the tire. If the tire and wheel were laid flat on the driveway and a line traced around the outside of it, such a line would form a circle which would represent the circumference (not the part inside of the circle, just the circle itself)

If the tire and wheel measure 20 inches across from one side to the other across the center, then that measurement is said to be the diameter.

To calculate the circumference of such a 20 inch wheel and tire (actually too small for most cars) you would multiply it by an unchanging number (called a constant) with the value of 3.1416.

This particular constant is called Pi (pie) and is actually very long beyond the decimal point. In fact, it can be proven that it has no end but simply goes on and on and on (the "Energizer Bunny" of constants). Most of the time, using 3.1416 is plenty accurate.

Anyhow, in the case of our 20" diameter wheel and tire, the circumference would be 20 " x 3.1416 or 62.83 inches - a bit more than 5 feet. You could check this by taking a tape measure and simply measuring around the outside of the wheel and tire.

To go a little further, every time the wheel rotated one turn, the car would have moved 62.83 inches or 5.23 feet.

If the car was moving at 60 miles per hour, it would be covering 88 feet every second so that wheel and tire would have to be turning at a rate of 16.8 rotations (revolutions) each second or (multiplying by 60 seconds in a minute) 1008.6 revolutions per minute (RPM). Speeds of rotating equipment are usually given in RPM's.

Probably TMI but hopefully of some help!

Answer 2

the easiest way to explain what the circumfrence is to say it's how long a circle is. in other words, if you were to take the line that makes a circle and stretch out into a straight line that would be the same measurement as the circumfrence
you calulate by multipling the diameter (the length of circle as measured in the middle) by pi (which is approximately 3.14)
hope that helps.

Answer 3

It is the measurement of the outside of the circle.....

The diameter of a circle is 3 centimeters. What is the circumference?
Solution:
= 3.14 · (3 cm)
= 9.42 cm

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The radius of a circle is 2 inches. What is the circumference?
Solution:
= 2 · (2 in)
= 4 in

= 3.14 · (4 in)
= 12.56 in

Answer 4

The circumference of a circle is defined to be pi (3.1415926536...) times the diameter (or pi times twice the radius) of a circle. If the circle's radius is 2, then the circumference of the circle would be 4pi.

Answer 5

It is the perimeter of something round.