C=2×p.i. ×r
C=2 ×pi ×11.2
=22.4pi
=70.37cm
A=pi ×r2
=pi ×11.2 square
=125.44pi
=394.081cm square
the diameter of a circle is two times the radius
You can either measure it, or calculate it if you know the diameter (radius = diameter / 2), or the circumference (radius = circumference / (2pi)).
You can measure it. Otherwise, you certainly have to know SOMETHING about the circle to calculate the radius, usually the diameter, the circumference, or the area. If you don't know anything at all about a circle, you can't find out the radius, either.
If you know the circumference, the ration of the diameter to the circumference is π, so diameter = circumference/π If you have the radius, diameter = 2 x radius
If by "it" you mean a circle, once you know the diameter, you can calculate its radius, its circumference, and its area.
To calculate this you will need the diameter of the circle. The formula is: diameter/2*pi If you don't know the diameter you can also use the area of the circle: Sqrt(Area/pi) = radius
You use the information that you do have, and a formula that relates it to theradius or diameter of the circle. As an example: The circumference is very helpfulif you know it.
Depends on what you know. Like if you know the radius, square it and multiply it by pi. If you know the diameter, do the same thing as you do with the radius except do it after finding half of that diameter.
Assuming you are talking about a circle:* If you know the radius of the circle, multiply that by 2. * If you know the circumference of the circle, divide that by pi. * If you know nothing, you need to measure either the radius, the diameter, or the circumference.
Based on what? - The radius is 1/2 the diameter. If it is the circumference you know, divide it by (2 x pi).
To know what a radius is you have to kno what a diameter is. The diameter is the distance accross a circle through its center. The radius is half the diameter.
You measure it. If you know the radius (of a circle), you multiply it by 2 to get the diameter. If you know the circumference of a circle, you divide by pi to get the diameter.You measure it. If you know the radius (of a circle), you multiply it by 2 to get the diameter. If you know the circumference of a circle, you divide by pi to get the diameter.You measure it. If you know the radius (of a circle), you multiply it by 2 to get the diameter. If you know the circumference of a circle, you divide by pi to get the diameter.You measure it. If you know the radius (of a circle), you multiply it by 2 to get the diameter. If you know the circumference of a circle, you divide by pi to get the diameter.
Diameter = 2*Radius