A sphere is defined geometrically as the set of all points in space that are equidistant from a given point. Since the distance from that point is the same in all directions, a sphere is like a 3-dimensional extension of a circle. The height, width, and length of a sphere are all equal, and that dimension is called the sphere's radius.
You have encountered spheres before in your previous mathematics classes. Before looking more closely at the formula for the surface area of a sphere, sort the following objects into two groups: spheres and non-spheres.
Drag the names of the objects to the correct column.
For each of the non-spheres, why are those objects not considered spheres?
Interactive popup. Assistance may be required.
A football is not a sphere because it is longer than it is wide, and a sphere has equal length, width, and height.
A bicycle wheel is not a sphere because even though it is round, it has a flat dimension that is not equal to the others.
A donut is not a sphere because it has a hole in the middle.
A car tire is not a sphere because even though it is round, it has a flat dimension that is not equal to the others.
