With a ruler, or other suitable length measuring device.
Measure the diameter (the widest part of the circle). The radius is half the diameter.
Well, if you know the diameter you divide that by two to get the radius.
Circumference=2*pi*radius
radius = circumference/2*pi
You can either measure it, or calculate it if you know the diameter (radius = diameter / 2), or the circumference (radius = circumference / (2pi)).
Divide the circumference by 2*pi will give the radius of the circle.
Well, if you know the diameter you divide that by two to get the radius.
Dividing the circumference by 2*pi will give the value of the radius.
Circumference=2*pi*radius
Circumference of a circle = 2*pi*radius
If you know the circumference of a circle, you can find the radius by dividing the circumference by the value of Pi (3.14159...)
Radius (not raduis) =circumference/(2*pi)
radius = circumference/(2*pi)
radius = circumference/2*pi
You can either measure it, or calculate it if you know the diameter (radius = diameter / 2), or the circumference (radius = circumference / (2pi)).
The equation for circumference is C=2(pi)(r) where C is the circumference and r is the radius. You can find the radius by plugging in the circumference into this equation and solving the equation.
The circumference of a circle that has a radius of 5 inches is 10 X pi or approximatly 31.415926535897932384626433832795. If you know the radius you can find the circumference by multiplying it by 2(pi)
Where C=circumference, r= radius and d=diameter To find circumference: C=2 x pi x r or you can use the formula C=pi x d To find diameter just multiply the radius by 2 if you know what the radius is. If you do not know the radius, but you know the circumference and need diameter use the following formula: C/pi=d Happy Computing!!!