Oblate Spheroid
High School
Definition
A name for a flattened sphere. It is obtained when you revolve an ellipse about its minor axis. A popular example for an oblate spheroid is the Earth. Due to earth's rotation, Earth has been flattened from its poles creating a shape that resembles an oblate.
Worked examples
\(\)Ellipse with semi-major axis \( a = 5 \) and semi-minor axis \( b = 3 \) revolved about the minor axis\(\)
Rotating the ellipse around its shorter axis creates an oblate spheroid flattened at the poles.
\(\)Earth: equatorial radius \( \approx 6378 \) km, polar radius \( \approx 6357 \) km\(\)
Earth is wider at the equator than pole-to-pole, making it an oblate spheroid.
Common mistakes
- Revolving an ellipse about its major axis creates an oblate spheroid → Revolve about the minor (shorter) axis to get an oblate spheroid Rotating about the major axis gives a prolate (elongated) spheroid instead.
- An oblate spheroid is stretched at the poles → An oblate spheroid is flattened at the poles Oblate means compressed; the equator bulges out while the poles are squashed.
- All spheroids are oblate → Spheroids can be oblate (flattened) or prolate (elongated) The axis of revolution determines whether you get oblate or prolate.
Where you'll use it next
You'll use oblate spheroids in calculus when computing volumes of solids of revolution, in physics and astronomy when modeling planetary shapes, and in geography when working with accurate Earth coordinate systems.
Found in 1 StudyPug lesson
Surface area and volume of spheres
10th Grade10thGeometry
A basketball is a sphere. Soap bubbles are usually spheres. A vitamin capture is a combination of cylinder and sphere. In this lesson, we will learn how to calculate the surface area and volume of spheres and composite solids.
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026