What is a matrix?

A matrix is defined as an arrangement of numbers in rows and columns, which is a fundamental concept in mathematics, particularly in linear algebra. This arrangement allows for the representation of data and mathematical relationships in a structured format. Each individual number in a matrix is referred to as an element or entry, and the dimensions of a matrix are described by the number of rows and columns it contains.

Matrices are widely used in various applications, including solving systems of equations, transformations in geometry, and data analysis. The ability to manipulate these arrangements—for instance, through addition, multiplication, or finding determinants—makes them a powerful tool in both theoretical and applied mathematics.

In contrast, the other options do not accurately define a matrix. A geometric shape of oceans does not relate to the numerical structure described. A method of calculation in trigonometry and a measurement of angles focus on different mathematical concepts and do not connect to the properties or uses of a matrix. Hence, the concept of a matrix as a structured arrangement of numbers is distinct and essential in mathematical discussions.