**Q: **Is a three-dimensional space given by an ordered triple of real numbers? ¶

**A: **Yes, and each number giving the distance of that point from the origin measured along the given axis, which is equal to the distance of that point from the plane determined by the other two axes.

**Q: **Is a three-dimensional space found in linear algebra? ¶

**A: **Yes, where the idea of independence is crucial.

**Q: **Is a three-dimensional space the two-dimensional subspaces? ¶

**A: **Yes, that is, the planes.