Basic Math Terms And Concepts

Front 1

absolute value

Back 1

The magnitude of a number irrespective of its sign. Written as a number inside vertical lines: I3I=3 and I-3I=3.

Front 2

acute angle

Back 2

An angle measuring less than 90 degrees. A triangle with three acute angles is called an acute triangle.

Front 3

angle

Back 3

Two line segments coming together at a point called the vertex.

Front 4

area

Back 4

A measure, in square units, of the size of a region in a plane. Finding the area of a figure usually involves multiplying two dimensions, such as length and width, or base and height. The area of a circle is multiplying pi by the square of the radius.

Front 5

composite number

Back 5

An integer that has more factors than one and itself; for example, a nonprime integer greater than 1. The first ten composite integers are 4, 6, 8, 9, 10, 12, 14, 15, 16, and 18.

Front 6

complementary angles

Back 6

Two angles whose measures add up to 90 degrees. A 30 degree angle and a 60 degree angle are complementary.

Front 7

cone

Back 7

A solid generated by rotating a right triangle about one of its legs; also called a right circular cone.

Front 8

cube

Back 8

A rectangular solid whose faces are all squares.

Front 9

edge

Back 9

A line segment formed by the intersection of two faces of a three-dimensional shape.

Front 10

dividend

Back 10

A number to be divided; for example, in 12 /3=4, 12 is the dividend.

Front 11

divisor

Back 11

A number that divides into another number; for example, in 12/3=4, 3 is the divisor.

Front 12

ellipse

Back 12

An oval shape, literally a set of points in a plane for which the sum of the distances from two points (called foci) is constant.

Front 13

equilateral triangle

Back 13

A triangle with three equal sides and three equal angles of 60 degrees.

Front 14

even number

Back 14

An integer that is a multiple of 2. The set of even numbers not only includes 2, 4, 6, etc., but also 0, -2, -4, -6, etc.

Front 15

face

Back 15

A polygon formed by the edges of a solid.

Front 16

factor (of n)

Back 16

A + integer that divides into n with no remainder; for example, the complete list of factors of factors of 18 is: 1, 2, 3, 6, 9, and 18.

Front 17

hypotenuse

Back 17

The side of a right triangle opposite the right angle. Note: the hypotenuse is always the longest side; if c is the hypotenuse and a and b are the legs of a right triangle. c2=a2 + b2.

Front 18

imaginary number

Back 18

A number that cannot be represented on the number line because it contains a factor of i, which is the square root of -1. Thus, for example, (3i)2 = -9.

Front 19

integer

Back 19

Any of the natural numbers (also known as "whole numbers"), the negatives of these numbers, or zero.

Front 20

isosceles

Back 20

A triangle with two sides of equal length.

Front 21

legs

Back 21

The two sides of a right triangle that are not the hypotenuse--that are not opposite the right angle.

Front 22

multiple (of n)

Back 22

A number that n will divide into with no remainder. Some of the multiples of 18 are 0, 18, 36, 54, 72, and 90.

Front 23

obtuse

Back 23

An obtuse angle measures more than 90 degrees and less than 180 degrees. An obtuse triangle is one that has one obtuse angle.

Front 24

odd number

Back 24

An integer that is not a multiple of 2. Any integer that's not even is odd.

Front 25

parallelogram

Back 25

A quadrilateral with two parallel sides.

Front 26

perimeter

Back 26

The sum of the lengths of the sides of a polygon. Two polygons with the same area do not necessarily have the same perimeter.

Front 27

perpendicular

Back 27

Intersecting at a right angle. The altitude and base of a triangle are perpendicular.

Front 28

pi

Back 28

An irrational number, with its own symbol, approximately = to 3.14, which is equal to the ratio of the circumference of any circle to its diameter. The area of a circle equals pi r 2 and the circumference equals 2 pi r.

Front 29

power

Back 29

A product obtained by multiplying a quantity by itself one or more times; for example, the fifth power of 2 is 32.

Front 30

prime number

Back 30

An integer greater than 1 that has no factors other than 1 and itself. The first 10 prime numbers are: 2, 3, 5, 7, 11, 13, 17, 23, 29, and 31. Notice that 2 is the only even prime number.

Front 31

product

Back 31

The result of multiplication. The product of 3 and 4 is 12.

Front 32

pyramid

Back 32

A polyhedron having for its base a polygon and for faces triangles with a common vertex.

Front 33

Pythagorean Theorem

Back 33

The rule that states, "For any right triangle, the sum of the squares of the legs is equal to the square of the hypotenuse" (or a2 + b2 = c2).

Front 34

quadrilateral

Back 34

A four-sided polygon. Squares, rectangles, parallelograms, and trapezoids are all quadrilaterals.

Front 35

quotient

Back 35

The result of division. When 12 is divided by 3, the quotient is 4.

Front 36

radical

Back 36

Symbolized by an elongated check mark, which by itself represents the square root. With a little number written in (as in 3v--8 = the cube root of 8, or 2), it represents a higher root. By convention, represents the positive root only.

Front 37

radius

Back 37

The length of a line segment connecting the center and a point on a circle. The radius is half the diameter.

Front 38

real

Back 38

Having a place on the number line (as opposed to imaginary numbers). For instance, pi is a real number because it has a location on the number line (somewhere just to the right of 3.14).

Front 39

reciprocals

Back 39

A pair of numbers whose products is 1. To get to the reciprocal of a fraction, switch the numerator and denominator: the reciprocal of 2/7 is 7/2.

Front 40

rectangle

Back 40

A quadrilateral with four right angles. All rectangles are parallelograms, but not all parallelograms are rectangles.

Front 41

rhombus

Back 41

A quadrilateral with four = sides, eg. diamond.

Front 42

right angle

Back 42

An angle measuring exactly 90 degrees.

Front 43

root

Back 43

A number that multiplied by itself a certain number of times will yield the given quantity; for example, the square root of 4 is 2, and the cube root of 8 is 2.

Front 44

scalene triangle

Back 44

A triangle with sides of different lengths. A 3-4-5 triangle is a scalene triangle.

Front 45

solid

Back 45

A three-dimensional figure.

Front 46

supplementary angles

Back 46

Two angles whose measures add up to 180 degrees.

Front 47

trapezoid

Back 47

A quadrilateral with two parallel sides and two nonparallel sides.

Front 48

torus

Back 48

A doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle.

Front 49

volume

Back 49

The amount of three-dimensional space taken up by a three-dimensional object.