Have you begun studying for the GRE quantitative reasoning sections? Are you being held up by the recurring appearance of math terms whose definitions you don’t fully understand? We are here to help! Read through our glossary of math terms to know for GRE quantitative reasoning.

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** GRE Geometry Terms**

**Acute angle** – an angle of less than 90 degrees

**Area** – a measure of the two-dimensional space enclosed by a circle or polygon

**Bisect** – to divide into two equal lengths or areas

**Complementary** – of two angles with a sum of 90 degrees

**Congruent** – having the same shape and size (for polygons, sides, or angles)

**Coordinate plane** – the two-dimensional grid network formed by the X and Y axes

**Cube** – a regular rectangular prism (each of the six sides is a square)

**Cylinder** – a prism with circular ends

**Equidistant** – of two points, being the same distance from another point or line

**Interior angle** – an angle inside a polygon formed by two sides meeting at a vertex

**Intersect(ion)** – of two lines, to meet and cross, or the point at which two lines meet and cross

**Obtuse angle** – and angle more than 90 degrees and less than 180 degrees

**Parallel** – lines, segments, or sides that run exactly the same direction

**Perimeter** – the distance around a polygon, the sum of the lengths of its sides

**Perpendicular** – lines, segments, or sides that meet or would meet at a 90-degree angle

**Polygon** – an enclosed shape of line segments (sides) meeting at angles

**Prism** – a solid made by adding height/depth to a circle or polygon

**Regular** – of a polygon, having sides of equal length and angles of equal measure

**Rectangular prism** – a box of six rectangular sides

**Reflex angle** – an angle greater than 180 degrees and less than 360 degrees

**Right angle** – a 90-degree angle

**Similar** – having the same shape but not necessarily the same size (for polygons)

**Slope** – the “steepness” of a line, its ratio of upward “motion” to rightward “motion”

**Solid** – a three-dimensional shape

**Supplementary** – of two angles with a sum of 180 degrees

**Vertex** – a point on a polygon where two sides meet

**Volume** – a measure of the three-dimensional space enclosed by or taken up by a solid

**X-axis** – the horizontal axis of the coordinate plane

**X-intercept** – a point at which a line or graph crosses the x-axis

**Y-axis**– the vertical axis of the coordinate plane

**Y-intercept** – a point at which a line or graph crosses the y-axis

**Circles**

**Arc** – a segment of a circle’s circumference

**Central angle** – an angle formed between a circle’s center and two points on its edge

**Circumference** – the distance around a circle

**Diameter** – the longest distance across a circle (through the center)

**Radius** – the distance from a circle’s center to its edge

**Sector** – a “pie slice” of a circle created by a central angle

**Quadrilaterals**

**Parallelogram** – opposite sides parallel and of equal length

**Rectangle** – angles each 90 degrees, opposite sides of equal length

**Square** – angles each 90 degrees, sides of equal length

**Trapezoid** – one set of parallel sides

**Triangles**

**30-60-90** – a right triangle with angle measures of 30, 60, and 90 degrees

**45-45-90** – a right isosceles triangle (with angle measures of 45, 45, and 90 degrees)

**Base** – the length of a side perpendicular to a height

**Equilateral** – all sides are the same length

**Height** – the measure of perpendicular distance from a side designated as a base to the vertex opposite

**Hypotenuse** – the longest side of a right triangle, across from the 90-degree angle

**Isosceles** – two sides are the same length, and the third side is a different length

**Legs** – the two shorter sides of a right triangle, meeting at the 90-degree angle

**Right** – one angle is 90 degrees

**Scalene** – no sides are the same length

**GRE Arithmetic/Algebra Terms**

**Absolute value** – a value’s distance from zero (always positive)

**Base** – a value or variable being raised to a power by a notated exponent

**Coefficient** – in an expression or equation, a value in multiplication with a variable

**Constant** – in an expression or equation, a value not in multiplication or division with any variable

**Denominator** – the lower part of a fraction

**Equation** – a mathematical “statement” of the equivalent value of two expressions

**Exponent** – a superscripted value or variable indicating the power to which a given base is to be raised

**Expression** – mathematical notation of operations to be performed between values and variables

**Index** – a value or variable used in conjunction with a radical to indicate the root to be taken from a given value or variable

**Inequality** – a mathematical “statement” of the comparative values of two or more expressions

**Numerator** – the upper part of a fraction

**Power** – a number of times for a given value to be multiplied by itself

**Radical** – a symbol used to indicate a specified root of a given value or variable

**Reciprocal** – the “flip” of a fraction, or the fraction resulting when a value or variable is made the denominator of a fraction with a numerator of 1

**Root** – a value that, when raised to a specified power, equals a given value

**Units digit** – the digit in the “ones place,” the digit immediately to the left of the decimal

**Variable** – an “unknown” or “replaceable” value, represented by an italicized English or, sometimes, Greek letter

**GRE Number Properties Terms**

**Arithmetic sequence** – a sequence of values differing from one to the next by the same amount, equidistant on a number line (6, 8, 10, 12, 14) (27, 35, 43, 51, 59)

**Divisible** – able to be divided evenly into a given number of groups or pieces

**Divisor** – in integer by which a given integer is divisible (interchangeable with factor)

**Even** – an integer divisible by 2 (a multiple of 2, but 0 is also even)

**Factor** – an integer that, when multiplied by some integer, produces a given value (interchangeable with divisor)

**Geometric sequence** – a series of values changing by the same factor from one to the next (5, 15, 45, 135, 405) (8, 32, 128, 512, 2048)

**Greatest common factor** – the largest integer that is a factor of each integer in a given set

**Integer** – a whole number (whether positive, negative or 0)

**Multiple** – an integer that is divisible by a given integer (15, 84, and 321 are multiples of 3)

**Least common multiple** – the smallest integer that is a multiple of each integer in a given set

**Odd** – an integer nor divisible by 2 (not a multiple of 2)

**Prime number** – a number with no factors besides 1 and itself

**Remainder** – the number left over or left out when an integer does not divide evenly into a given number of groups (17 / 5 has remainder 2 because if 17 things are split into 5 equal groups (of 3), 2 things will be left over)

**GRE Statistics Terms**

**Mean** – the value that results from dividing the sum of the values in a data set by the number of values in the set (sometimes “arithmetic mean”)

**Median** – the “middle value” in a data set, or, in the case of an even number of values, the mean of the two middle values (1, 1, 2, 3, 5 has median 2; 1, 1, 2, 3, 5, 8, 13, 21 has median 4)

**Mode** – the value with the most instances or occurrences in a data set

**Percentile** – a measure of the percentage of values in a data set that are equal to or less than a given value (in a data set comprising the integers from 1 through 100, inclusive, 34 is at the 34th percentile, 79 is at the 79th percentile)

**Quartiles** – the values at the 25th, 50th, 75, and 100th percentiles: Q1, Q2, Q3, and Q4, respectively (in a data set comprising the integers from 1 through 100, inclusive, Q1 is 25, Q2 is 50, Q3 is 75, and Q4 is 100)

**Range** – the difference between the highest and lowest values in a data set

**Standard deviation** – the average (positive) amount by which a value in a data set differs from the mean of the set.

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**Contributor:** *Elijah Mize (Apex GRE Instructor)*