if the segment is the whole length of the circle divide it by 2
You already know the radius.
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
measure it
radius = circumference/(2*pi)
radius = circumference/2*pi
Area of Circle = pi (radius)2 So , using this formula we can find the radius and also the diameter. Diameter = 2(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.
Area of a circle = pi*radius2
Well, if you know the diameter you divide that by two to get the radius.
Multiply by two. The diameter is twice the radius.
Radius = +sqrt(Area/pi)