MTEL Math Terms & Formulas

area of a triangle

(1/2) base x height

slope

(y2 - y1) / (x2 - x1), i.e. rise/run

number line

A graphical representation of the relationships between numbers. Numbers on a number line (1) always increase as you move to the right, and (2) are equally spaced.

radius of a circle

A line segment extending from the center of the circle to a point on the circle.

diameter of a circle

A line segment that passes through the center and has its endpoints on the circle.

line of symmetry

A line that divides a figure into two congruent parts, each of which is a mirror image of the other.

rational number

A number that can be formed by dividing one integer by another. E.g. 1/2 (1 divided by 2), 0.75 (3 divided by 4); 5 (10 divided by 2), 2.12 (53 divded by 25)

real number

A number that is not imaginary. E.g. 1, 15.82, -0.1, 3/4

composite number

A number that is not prime (i.e. has factors other than 1 and itself).

rectangle

A parallelogram whose angles measure 90 degrees.

prime number

A positive integer greater than 1 that has exactly two whole-number factors: itself and the number 1. Ex. 2, 3, 5, 7, 11, 13, 17, 19

factor

A positive integer that goes evenly into a number (without leaving a remainder). Ex. Factors of 12 are: 1, 2, 3, 4, 6, 12

whole number

A positive, non-fractional/non-decimal number. E.g. 1, 23, 45, 78

parallelogram

A quadrilateral in which the opposite angles are of equal measure and the opposite sides are of equal length.

rhombus

A quadrilateral with four equal sides.

square

A rectangle in which the lengths of all the sides are equal.

function

A rule or formula that tells how to associate the elements in one set with the elements in another set.

prism

A solid (three-dimensional figure) in which two congruent polygons are joined by rectangular faces that are perpendicular to the polygons.

right triangle

A triangle with a right angle (90 degrees).

equilateral triangle

A triangle with three equal sides and three equal angles (all 60 degrees).

isosceles triangle

A triangle with two equal sides and two equal angles.

consecutive

Following in sequence. E.g. 1, 2, 3, 4 (consecutive integers)

perpendicular lines

Lines that form a 90 degree angle. The product of their slopes is -1.

parallel lines

Lines whose slopes are equal.

translation

Movement of a shape without any rotation or reflection.

multiple

Numbers that can be divided by some given number without a remainder. Ex. Multiples of 8 include: 8, 16, 24, 32, 40, 48.

reflection

Producing a mirror image of an object with respect to a line, which is called the line of reflection.

circumference

The distance around a circle. The formula for circumference is 2πr, where r = radius.

absolute value

The distance from zero on the number line.

least common factor (LCF)

The largest common factor of two (or more) numbers. E.g. 6 is the GCF of 12 and 18

median

The middle value of a list when the list of numbers is in order from least to greatest. Note: when there is an even number of numbers in the list, the median is the midpoint of the two middle numbers.

domain

The set of all the values for which a function is defined (in the coordinate plane, the x values).

range

The set of all values that are the output, or result, of applying a function (in the coordinate plane, the y values).

hypotenuse

The side of a triangle opposite a right angle. The hypotenuse is always the longest side.

least common multiple (LCM)

The smallest multiple of two (or more) numbers. E.g. 24 is the LCM of 8 and 12.

mean

The sum of a list of values divided by the number of values in the list.

perimeter

The sum of the lengths of the sides of a polygon.

vertical angles

The two opposite angles formed by two intersecting lines. Vertical angles have the SAME MEASURE.

mode

The value or values that appear the greatest number of times in a set/list.

integer

The whole numbers and their negatives (including zero) ... , -3, -2, -1, 0, 1, 2, 3, 4, ...

natural number

The whole numbers from one upwards. ... , 1, 2, 3, 4, 5, ...

similar triangles

Triangles that have the same shape. The corresponding angles have the same measure, and the corresponding sides are proportional.

congruent triangles

Triangles with the same size and shape.

rotation

Turning an object around a point, which is called the center of rotation.

supplementary angles

Two angles whose measures have a sum of 180 degrees.

Pythagorean theorem

a^2+b^2=c^2, where c = hypotenuse

area of a rectange

length x width

volume of a rectangular solid

length x width x height

linear equation (slope-intercept form)

y=mx+b, where m = slope and y = the y-intercept

volume of a cylinder

πr^2 x height, where r = radius of the base

area of a circle

πr^2, where r = radius