Triangular Cupola
 |
Johnson Solid 
. The bottom six Vertices are
and the top three Vertices are
See also Johnson Solid
- Roulette
- Round
- Rounding
- Routh-Hurwitz Theorem
- Routh's Theorem
- RSA Encryption
- RSA Number
- Rubber-Sheet Geometry
- Rubik's Clock
- Rubik's Cube
- Rudin-Shapiro Sequence
- Rudvalis Group
- Rule
- Ruled Surface
- Rule of 72
- Ruler
- Ruler Function
- Ruling
- Run
- Runge-Kutta Method
- Runge-Walsh Theorem
- Running Knot
- Russell's Antinomy
- Russell's Paradox
- Russian Multiplication