What is a Sphere?

What is the relationship between a hemisphere, a cone, and a cylinder? Using Cavalieri's Principle, the class determines that the sum of the volume of a hemisphere and a cone with the same radius and height equals the volume of a...

A diameter is the longest chord possible, but that's not the only relationship between chords and diameters! Young geometry pupils construct perpendicular bisectors of chords to develop a conjecture about the relationships between chords...

Learners find the volume of spheres. For this geometry lesson, students measure and derive the formula for each shape and solid. They use the correct terminology and units when solving these problems.

When mathematical errors happen, part of the learning is to figure out how it affects the rest of your calculations. The activity has your mathematicians solving for the area of a circular pipe and taking into consideration any errors...

Putting a rectangular object into a circular one—didn't the astronauts on Apollo 13 have to do something like this? Learners first construct the center of a circle using perpendiculars. They then discover how to inscribe a rectangle in a...

A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...

Pie is great for finding pi. A short video shows how to use real pies to calculate pi. The method involves laying out pies along the circumference and along the diameter of a circle, and then finding the ratio of the number of pies.

The teacher diagrams and explains the different terms of what comprises a sphere. Follow along and learn about the: radius, diameter, great circle, center, and hemisphere.

This webpage thoroughly discusses the math of spheres. Includes the equation for a sphere in Cartesian and spherical coordinates as well as parametrically. Surface Area, volume, and curvature are addressed at this extensive site.

This site shows what a diameter is, how to find one on a circle or a sphere, and provides the formula to find diameter of a circle or "the great circle of a sphere.