The radius is half the diameter, so use the formula r = D/2. This is identical to the method used for calculating the radius of a circle from its diameter. If you have a sphere with a diameter of 16 cm, find the radius by dividing 16/2 to get 8 cm. If the diameter is 42, then the radius is 21. Use the formula C/2π. Since the circumference is equal to πD, which is equal to 2πr, dividing the circumference by 2π will give the radius.  If you have a sphere with a circumference of 20 m, find the radius by dividing 20/2π = 3.183 m. Use the same formula to convert between the radius and circumference of a circle. Use the formula ((V/π)(3/4))1/3. The volume of a sphere is  derived from the equation V = (4/3)πr3.  Solving for the r variable in this equation gets ((V/π)(3/4))1/3 = r, meaning that the radius of a sphere is equal to the volume divided by π, times 3/4, all taken to the 1/3 power (or the cube root.) If you have a sphere with a volume of 100 inches3, solve for the radius as follows:  ((V/π)(3/4))1/3 = r ((100/π)(3/4))1/3 = r ((31.83)(3/4))1/3 = r (23.87)1/3 = r  2.88 in = r Use the formula r = √(A/(4π)). The surface area of a sphere is derived from the equation A = 4πr2. Solving for the r variable yields √(A/(4π)) = r, meaning that the radius of a sphere is equal to the square root of the surface area divided by 4π. You can also take (A/(4π)) to the 1/2 power for the same result. If you have a sphere with a surface area of 1,200 cm2, solve for the radius as follows:  √(A/(4π)) = r √(1200/(4π)) = r √(300/(π)) = r √(95.49) = r  9.77 cm = r
جد نصف القطر إذا عرفت القطر. جد نصف القطر بمعرفة المحيط. احسب نصف القطر بمعرفة حجم الكرة. جد نصف القطر من مساحة السطح.
جد نصف القطر إذا عرفت القطر. جد نصف القطر بمعرفة المحيط. احسب نصف القطر بمعرفة حجم الكرة. جد نصف القطر من مساحة السطح.