Dimensions of a Matrix

-- The dimension of a matrix consist of the rows and columns that make it up.
          -Columns: vertical
          -Rows: horizontal

--When figuring out what the dimension of a matrix is you ALWAYS put the row first, then the columns.

This matrix has a dimension of 1x3 because it has one row(horizontal) and 3 columns(vertical)

This matrix has a dimension of 3x3 because it has 3 rows and 3 columns

This matrix has a dimension of 2x3 because it has 2 rows and 3 columns

This dimension is known as the Indentity Matrix (serves as the mulitplicative identity. This is also known as a 3x3 matrix since it has 3 rows and 3 columns.