# Mathematical Dictionary - Letter A

ABACUS - Instrument for counting and calculation. Calculator with several metal rods, holding balls that can be manipulated, serving to perform mathematical operations. ABSCISSA - Axis coordinate name x in a two-dimensional Cartesian system.

ADDITION - One of four basic arithmetic operations, used to add one number to another.

ALPHA ( ) - First letter of greek alphabet.

DIGITAL - Symbols used to represent numbers. In our base numbering system 10, there are ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

LINEAR ALGEBRA - Branch of Mathematics that uses some fundamental concepts and structures, such as: vectors, vector spaces, linear transformations, systems of linear equations and matrices.

Algorithm - A set of rules required to solve a problem or calculation.

ALIQUOT - Percentage with which a certain tax is levied on the value of the taxed object.

HEIGHT - Dimension of a body considered vertically from bottom to top.

SAMPLE - A set chosen to represent a collection or population.

RANGE OF AN INTERVAL - It is the difference between the upper and lower end of the range. Also called gap diameter.

ANGLE - Angle is the joining of two oriented straight line segments (or two oriented straight lines) from a common point. The intersection between the two segments (or half-straight) is called the vertex of the angle and the sides of the angle are the two segments (or half-straight).

ADJACENT ANGLE - Angle with one vertex and one common side. The angles GED and DEF are adjacent. ACUTE ANGLE - Angle measuring less than 90º and more than 0º.

ANGLE OBTUSE - Angle measuring more than 90º and less than 180 degrees.

Shallow Angle - Angle that measures exactly 180º.

STRAIGHT ANGLE - Angle that measures exactly 90º.

ADDITIONAL ANGLES - Angles whose sum is equal to 90º.

ADDITIONAL ANGLES - Two angles are said to be supplementary when their sum is 180º.

RING (Geometry) - Plane portion delimited by two circles with the same center.

YEAR - Time period comprising 365 days, except the leap year, which has 366 days.

APOTHEM - Perpendicular line segment next to a polygon drawn from its center.

APPROACH - Value obtained by rounding a measure. Example: If we rounded the number 6.851 we would have 6.85.

A - B - C - D - E - F - G - H - I / J / K - L - M - N - O - P - Q - R - S - T - U / V - X / Z