Finding the radius/area/volume of a sphere (ball) circumscribed around a cylinder

In this publication, we will consider how to find the radius of a sphere circumscribed around a right cylinder, as well as its surface area and the volume of a ball bounded by this sphere.

Finding the radius of a sphere/ball

About any one can be described (or in other words, fit a cylinder into a ball) – but only one.

Finding the radius/area/volume of a sphere (ball) circumscribed around a cylinder

  • The center of such a sphere will be the center of the cylinder, in our case it is a point O.
  • O1 и O2 are the centers of the bases of the cylinder.
  • O1O2 – cylinder height (H).
  • OO1 = OO2 = h/2.

It can be seen that the radius of the circumscribed sphere (ARE YOU), half the height of the cylinder (OO1)  and the radius of its base (O1E) form a right triangle OO1E.

Finding the radius/area/volume of a sphere (ball) circumscribed around a cylinder

Using this we can find the hypotenuse of this triangle, which is also the radius of the sphere circumscribed about the given cylinder:

Finding the radius/area/volume of a sphere (ball) circumscribed around a cylinder

Knowing the radius of the sphere, you can calculate the area (S) its surface and volume (V) sphere bounded by a sphere:

  • S = 4 ⋅ π ⋅ R2
  • S = 4/3 ⋅ π ⋅ R3

Note: π rounded equals 3,14.

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