Question: what are math words that start with r?
Answer: Radian. Radical. Radicand. Radius. Radius (polygon) Radix. Random. ... 
Rational Number. Ray. Real Number. Reciprocal. Rectangle. Rectangular Coordinates. Rectangular Prism. ... 
Regular Polygon. Regular Polyhedron. Relative Frequency. Relatively Prime. Remainder. Remainder Theorem. Rent. ... 
Rigid. Rise. Risk. Risk Management. RMS. Roman Numerals. Root.