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# What is an oblate spheroid and prolate spheroid?

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A spheroid is a geometric shape vaguely similar to that of a sphere. A sphere can be defined as the three-dimensional form of a circle. This means that the distance between the center of the sphere and any given point on the boundary of the sphere is constant. When it comes to a spheroid, this isn’t the case. A spheroid is not exactly round. A spheroid can be obtained when an Ellipse (a curve in a plane surrounding two focal points such that for every point of the curve, the sum of the distances to the two focal points is constant) is rotated about one of its principal axis.

There are two types of spheroids-

#### Prolate spheroid:

The Prolate spheroid is the kind of spheroid which is obtained when we rotate an ellipse around its major axis. This action results in a spheroid which looks like an elongated sphere. A lot of objects that we see and use on a daily basis can be seen having this shape.  A rugby ball and an egg are a couple of examples of objects in the shape of a prolate spheroid. #### Oblate spheroid:

The second type of spheroid is an oblate spheroid. This type of spheroid can be obtained when an ellipse is rotated about its minor axis. This action results in a spheroid which looks like a flattened or a contracted sphere. The biggest example for this kind of sphere is planet Earth. Planet Earth is supposed to be a sphere but due to the effects of gravitation and rotation, Earth’s shape is flattened and hence, it resembles the shape of an oblate spheroid. The spheroids are used extensively in the field of mathematics. They can often be seen in differential geometry and calculus. In recent years, Spheroids have also played a big role in cancer research as well. Especially when it comes to a better understanding of basic tumor biology as well as the responses to different agents with therapeutic potential, by using the multicellular spheroid tumor model system.