Basic Mathematical Terms and Concepts

Question 1

absolute value

Answer 1

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

Question 2

acute angle

Answer 2

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

Question 3

angle

Answer 3

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

Question 4

area

Answer 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 found by multiplying pi by the square of the radius.

Question 5

composite number

Answer 5

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

Question 6

complementary angles

Answer 6

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

Question 7

cone

Answer 7

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

Question 8

cube

Answer 8

A rectangular solid whose faces are all squares.

Question 9

edge

Answer 9

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

Question 10

dividend

Answer 10

A number to be divided (e.g., in 12 / 3 = 4, 12 is the dividend).

Question 11

divisor

Answer 11

A number that divides into another number (e.g., in 12 / 3 = 4, 3 is the divisor).

Question 12

ellipse

Answer 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.

Question 13

equilateral triangle

Answer 13

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

Question 14

even number

Answer 14

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

Question 15

face

Answer 15

A polygon formed by edges of a solid.

Question 16

factor (of n)

Answer 16

A positive integer that divides into n with no remainder (e.g., the complete list of factors of 18 is 1, 2, 3, 6, 9, and 18).

Question 17

hypotenuse

Answer 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 the right triangle, c^2= a^2 + b^2.

Question 18

imaginary number

Answer 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.

Question 19

integer

Answer 19

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

Question 20

isosceles triangle

Answer 20

A triangle with two sides of equal length.

Question 21

legs

Answer 21

The two sides of a right triangle that are not hypotenuse (i.e., are not opposite the right angle).

Question 22

multiple (of n)

Answer 22

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

Question 23

obtuse

Answer 23

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

Question 24

odd number

Answer 24

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

Question 25

parallelogram

Answer 25

A quadrilateral with two parallel sides.

Question 26

perimeter

Answer 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.

Question 27

perpendicular

Answer 27

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

Question 28

pi

Answer 28

An irrational number, represented by the symbol pi, approximately equal 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.

Question 29

power

Answer 29

A product obtained by multiplying a quantity by itself one or more times (e.g., the fifth power of 2 or 2^5 is 32).

Question 30

prime number

Answer 30

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

Question 31

product

Answer 31

The result of multiplication (e.g., the product of 3 and 4 is 12).

Question 32

pyramid

Answer 32

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

Question 33

Pythagorean theorem

Answer 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 a^2 + b^2 = c^2).

Question 34

quadrilateral

Answer 34

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

Question 35

quotient

Answer 35

The result of division (e.g., in 12 / 3 = 4, 4 is the quotient).

Question 36

radical

Answer 36

The symbol √, which by itself represents the square root. With a little number written in ( as in 3√8 = the cube root of 8, or 2), it represents a higher root. By convention, √ represents the positive root only.

Question 37

radius

Answer 37

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

Question 38

real

Answer 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).

Question 39

reciprocals

Answer 39

A pair of numbers whose product is 1. To get the reciprocal of a fraction, switch the numerator and denominator (e.g., the reciprocal of 2/7 is 7/2).

Question 40

rectangle

Answer 40

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

Question 41

rhombus

Answer 41

A quadrilateral with four equal sides.

Question 42

right angle

Answer 42

An angle measuring exactly 90 degrees.

Question 43

root

Answer 43

A number that multiplied by itself a certain number of times will yield the given quantity (e.g., the square root of 4 is 2, and the cube root of 8 is 2).

Question 44

scalene triangle

Answer 44

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

Question 45

solid

Answer 45

A three-dimensional figure.

Question 46

supplementary angles

Answer 46

Two angles whose measures add up to 180 degrees.

Question 47

trapezoid

Answer 47

A quadrilateral with two parallel sides and two nonparallel sides.

Question 48

torus

Answer 48

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

Question 49

volume

Answer 49

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