Are you looking for some math words that start with the letter R? Look no further, you have come to the right place.

In this article, I’m going to embark on a journey into the realm of math words that start with the letter R. From algebraic equations to awe-inspiring angles, these words hold the key to unlocking the beauty and complexity of the numerical world.

So, without any further ado, let’s dive into the captivating world of “Math Words That Start With R” and discover the beauty and relevance of arithmetic in our lives.

**Math Words That Start With R**

The followings are the math words that begin with the letter R (In alphabetical order):

**1. Radian:** A “radian” is a unit of measurement for angles in the International System of Units (SI). It is defined as the angle subtended at the center of a circle by an arc that is equal in length to the radius of the circle.

**2. Radical:** In mathematics, a “radical” is a symbol (√) used to denote the square root or other roots of a number or expression.

**3. Radicand:** The “radicand” is the number or expression placed inside a radical symbol, indicating the quantity for which the root is to be found.

**4. Radius:** The “radius” of a circle is the distance from the center of the circle to any point on its circumference. It is a fundamental element in circle geometry and is used to calculate various circle properties.

**5. Radix:** In the context of number systems, a “radix” is the base or the number of unique digits used to represent numbers. For example, in the decimal system, the radix is 10 because there are 10 unique digits (0 to 9).

**6. Random:** “Random” refers to the lack of predictability or pattern in an event or process. In probability theory, random events are those for which the outcome cannot be precisely determined in advance.

**7. Random Sample:** A “random sample” is a subset of a population selected in such a way that each member of the population has an equal chance of being included in the sample. It is a common technique used in statistics to make inferences about a population based on the characteristics of the sample.

**8. Range in Math:** In mathematics, “range” refers to the set of all possible output values or the difference between the largest and smallest values in a dataset.

**9. Range of a Function:** The “range of a function” is the set of all possible output values that the function can produce for a given set of input values.

**10. Rate:** A “rate” is a measure of one quantity per unit of another quantity. It is often used in ratio comparisons, such as speed, interest rates, or population growth rates.

**11. Rate of Return:** The “rate of return” is a financial metric used to measure the profitability of an investment over a specific period.

**12. Ratio:** A “ratio” is a comparison of two quantities expressed in the form of a fraction or division.

**13. Ratio to Percentage Conversion:** “Ratio to percentage conversion” involves converting a ratio to its equivalent percentage form.

**14. Rational Expression:** A “rational expression” is a fraction in which the numerator and denominator are polynomials.

**15. Rational Function:** A “rational function” is a function that can be expressed as the ratio of two polynomials.

**16. Rational Number:** A “rational number” is a number that can be expressed as a fraction of two integers, where the denominator is not zero.

**17. Ray:** In geometry, a “ray” is a part of a line that starts at a specific point (called the endpoint) and extends indefinitely in one direction.

**18. Real Number:** “Real numbers” are numbers that can be represented on the number line and include rational and irrational numbers.

**19. Reasonableness:** “Reasonableness” in mathematics refers to the logical soundness and practicality of a solution or answer.

**20. Reciprocal:** The “reciprocal” of a number is its multiplicative inverse, such that the product of a number and its reciprocal equals one.

**21. Reciprocal Identities in Trigonometry:** “Reciprocal identities” in trigonometry are a set of identities involving the reciprocals of trigonometric functions.

**22. Rectangle:** A “rectangle” is a four-sided polygon with opposite sides of equal length and four right angles.

**23. Rectangular Coordinates:** “Rectangular coordinates” (also known as Cartesian coordinates) are a system used to specify the position of a point in a plane by its distances from two perpendicular lines.

**24. Rectangular Prism:** A “rectangular prism” (also known as a rectangular cuboid) is a three-dimensional figure with six rectangular faces.

**25. Rectangular Pyramid:** A “rectangular pyramid” is a pyramid with a rectangular base and triangular faces that meet at a common vertex.

**26. Rectilinear Figure:** A “rectilinear figure” is a two-dimensional figure composed of straight lines.

**27. Recurrence Relation:** In mathematics, a “recurrence relation” is a sequence of numbers defined by relating each term to one or more previous terms in the sequence.

**28. Recurring Decimal:** A “recurring decimal” is a decimal number with a repeating pattern of digits after the decimal point.

**29. Recursion:** “Recursion” is a programming or mathematical concept where a function calls itself in its own definition.

**30. Recursive:** “Recursive” refers to a process or function that calls itself as part of its definition or execution.

**31. Reduce:** In fractions, “reduce” means to simplify the fraction by dividing both the numerator and denominator by their greatest common divisor.

**32. Reflection:** “Reflection” is a transformation in which a geometric figure is flipped over a line, creating its mirror image.

**33. Reflection Symmetry:** “Reflection symmetry” (or line symmetry) refers to the property of a figure that can be divided into two identical halves by a line of reflection.

**34. Reflex Angle:** A “reflex angle” is an angle that measures more than 180 degrees but less than 360 degrees.

**35. Reflexive Property:** In mathematics, the “reflexive property” states that any element is equal to itself.

**36. Regroup:** In arithmetic, “regrouping” or “carrying over” involves exchanging or regrouping units in one place value to another during addition or subtraction.

**37. Regular:** In geometry, “regular” refers to a shape with all sides and angles equal.

**38. Regular Polygon:** A “regular polygon” is a polygon with all sides and angles congruent.

**39. Regular Polyhedron:** A “regular polyhedron” is a three-dimensional solid with all faces congruent regular polygons.

**40. Related Facts:** “Related facts” are mathematical statements or problems that are connected or based on similar principles or concepts.

**41. Relative Frequency:** “Relative frequency” is the proportion of times an event occurs relative to the total number of trials or observations.

**42. Relatively Prime:** Two or more numbers are said to be “relatively prime” if their greatest common divisor is 1.

**43. Remainder:** The “remainder” is the amount left over after dividing one number by another.

**44. Remainder Theorem:** The “remainder theorem” states that when a polynomial is divided by a linear factor (x – a), the remainder is equal to f(a), where f(x) is the polynomial and a is the value at which it is evaluated.

**45. Rent:** In financial calculations, “rent” is the payment made by a tenant to a landlord for the use of property.

**46. Repeated Addition:** “Repeated addition” is a method of multiplication where the sum of the same number is calculated multiple times.

**47. Repeated Subtraction:** “Repeated subtraction” is a method of division where the dividend is successively reduced by the divisor until zero or the remainder is obtained.

**48. Repeating Decimal:** A “repeating decimal” is a decimal number in which one or more digits repeat infinitely.

**49. Result:** In mathematics, the “result” refers to the outcome or solution obtained after performing a calculation or operation.

**50. Retail Price:** The “retail price” is the price at which a product is sold to consumers.

**51. Revolution:** In geometry, “revolution” refers to the rotation of a two-dimensional figure around a fixed axis in three-dimensional space, creating a three-dimensional solid.

**52. Rhomboid Shape:** A “rhomboid” is a parallelogram with opposite sides parallel but not necessarily equal in length.

**53. Rhombus:** A “rhombus” is a parallelogram with all sides equal in length.

**54. RHS:** “RHS” stands for “right-hand side” and refers to the expression on the right side of an equation.

**55. Right Angle:** A “right angle” is an angle that measures exactly 90 degrees.

**56. Right Triangle:** A “right triangle” is a triangle with one 90-degree angle.

**57. Rigid:** In geometry, “rigid transformations” are transformations that preserve the shape and size of a figure.

**58. Rise:** The “rise” in mathematics refers to the vertical change between two points on a graph.

**59. Risk:** In finance and probability, “risk” refers to the uncertainty or chance of loss in an investment or an event.

**60. Risk Management:** “Risk management” involves strategies and techniques used to minimize or control potential losses in financial investments or projects.

**61. RMS:** “RMS” stands for “root mean square” and is a mathematical measure used to calculate the average of squared values.

**62. Roman Numerals:** “Roman numerals” are a system of numerical notation using letters of the Latin alphabet.

**63. Root:** In mathematics, a “root” of an equation is a value that satisfies the equation, making it true.

**64. Root Mean Square:** The “root mean square” is a statistical measure used to find the average value of a set of squared numbers.

**65. Rotation:** A “rotation” is a transformation that turns a figure around a fixed point by a certain angle.

**66. Rotational Symmetry:** “Rotational symmetry” refers to the property of a figure that remains unchanged after rotating it by a certain angle.

**67. Round a Whole Number:** “Rounding a whole number” involves approximating it to the nearest whole number or specified place value.

**68. Rounding:** “Rounding” is the process of approximating a number to a specified place value.

**69. Row:** In matrices, a “row” refers to a horizontal line of elements.

**70. RPM:** “RPM” stands for “revolutions per minute” and is used to measure the frequency of rotations or revolutions.

**71. Rule of 72:** The “rule of 72” is a simple formula used to estimate the time it takes for an investment to double, given a fixed annual rate of return.

**72. Ruler:** A “ruler” is a measuring instrument used to measure the length of objects.

**73. Rules of Divisibility:** “Rules of divisibility” are mathematical guidelines used to determine if one number can be divided by another without leaving a remainder.

**74. Run:** The “run” in mathematics refers to the horizontal change between two points on a graph.

I hope you found this article “Math Words That Start With R” helpful and informative.

Also, keep in mind that, this isn’t an exhaustive list, if there are any math words starting with the letter R.

Feel free to leave a comment below with the missing math word and I’ll update the list as soon as possible.

And, if you’d like to explore more math words starting with different letters of the alphabet, click the link below:

- Math Words That Start With S
- Math Words That Start With T
- Math Words That Start With U
- Math Words That Start With V