Basic Mathematical Terms and Concepts Flashcards
absolute value
The magnitude of a number, irrespective of its sign. Written as a number inside vertical lines: |3| = 3 and |-3| = 3.
acute angle
An angle measuring less than 90 degrees. A triangle with three acute angles is called an acute triangle.
angle
Two line segments coming together at a point called the vertex.
area
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.
composite number
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.
complementary angles
Two angles whose measures add up to 90 degrees. A 30 degree angle and a 60 degree angle are complementary.
cone
A solid generated by rotating a right triangle about one of its legs; also called right circular cone.
cube
A rectangular solid whose faces are all squares.
edge
A line segment formed by the intersection of two faces of a three-dimensional shape.
dividend
A number to be divided (e.g., in 12 / 3 = 4, 12 is the dividend).
divisor
A number that divides into another number (e.g., in 12 / 3 = 4, 3 is the divisor).
ellipse
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.
equilateral triangle
A triangle with three equal sides and three equal angles of 60 degrees.
even number
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.
face
A polygon formed by edges of a solid.
factor (of n)
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).
hypotenuse
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.
imaginary number
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.
integer
Any of the natural numbers (also known as “whole numbers”), the negatives of these numbers, or zero.
isosceles triangle
A triangle with two sides of equal length.
legs
The two sides of a right triangle that are not hypotenuse (i.e., are not opposite the right angle).
multiple (of n)
A number hat n will divide into with no remainder. Some of the multiples of 18 are 0, 18, 36, 54, 72, and 90).
obtuse
An obtuse angle measures more than 90 degrees and less than 180 degrees. An obtuse triangle is one that has one obtuse angle.
odd number
An integer that is not a multiple of 2. Any integer that is not even is odd.
parallelogram
A quadrilateral with two parallel sides.
perimeter
The sum of the lengths of the sides of a polygon. Two polygons with the same area do not necessarily have the same perimeter.
perpendicular
Intersecting at a right angle. The altitude and base of a triangle are perpendicular.
pi
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.
power
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).
prime number
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.
product
The result of multiplication (e.g., the product of 3 and 4 is 12).
pyramid
A polyhedron having for its base a polygon and for faces triangles with a common vertex.
Pythagorean theorem
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).
quadrilateral
A four-sided polygon. Squares, rectangles, parallelograms, and trapezoids are all quadrilaterals.
quotient
The result of division (e.g., in 12 / 3 = 4, 4 is the quotient).
radical
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.
radius
The length of a line segment connecting the center and a point on a circle. The radius is half the diameter.
real
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).
reciprocals
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).
rectangle
A quadrilateral with four right angles. All rectangles are parallelograms, but not all parallelograms are rectangles.
rhombus
A quadrilateral with four equal sides.
right angle
An angle measuring exactly 90 degrees.
root
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).
scalene triangle
A triangle with sides of different lengths. A 3-4-5 triangle is a scalene triangle.
solid
A three-dimensional figure.
supplementary angles
Two angles whose measures add up to 180 degrees.
trapezoid
A quadrilateral with two parallel sides and two nonparallel sides.
torus
A doughnut-shaped surface generated by a circle rotated about an axis in its plane that does not intersect the circle.
volume
The amount of three-dimensional space taken up by a three-dimensional object.
