> [!summary] Dimensions of a matrix describe the height and length of a matrix. > **Key Equations:** > Dimension Notation: $A_{m\times n}$ >[!info]+ Read Time **⏱ 1 min** # Definition The dimension of a [[Matrix Notation|matrix]] is the number of rows (equations) by the number of columns (variables). Dimensions tell us how high and long a matrix is. Mathematically, the dimensions of a matrix $A$ are referred to as the number of $m$ rows by $n$ column, described below. **$A_{m\times n}$ Matrix:** $ [A] = \left[ \begin{array}{cccc} a_{11} & a_{12} & \cdots & a_{1n} \\ a_{21} & a_{22} & \cdots & a_{2n}\\ \vdots & \vdots & \ddots & \vdots \\ a_{m1} & a_{m2} & \cdots & a_{mn} \end{array} \right] $ # Resources <iframe width="560" height="315" src="https://www.youtube.com/embed/ilFJYjfKYjk?si=3QleLsBaLErw2KcF" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>