It depends on the values you have. The base of a cylinder is a circle. If you know the circle's diameter, half it to find the radius. If you know the circle's circumference, divide by 2pi to find the radius. If you know the circle's area, divide by pi and take the square root to find the radius.
Diameter = 2*Radius
radius = circumference/2*pi
radius = circumference/(2*pi)
Area of a circle = pi*radius2
Area of Circle = pi (radius)2 So , using this formula we can find the radius and also the diameter. Diameter = 2(radius)
Well, if you know the diameter you divide that by two to get the radius.
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.
Multiply by two. The diameter is twice the radius.
Radius = +sqrt(Area/pi)
the radius is half of the diameter. and the middle of the circle is half way between this diameter.