A matrix with dimensions 3 × 7 has 3 rows and 7 columns.
The first number (3) represents the number of rows.
The second number (7) represents the number of columns.
The matrix A can be visualized as:
[ a₁₁ a₁₂ a₁₃ a₁₄ a₁₅ a₁₆ a₁₇ ]
[ a₂₁ a₂₂ a₂₃ a₂₄ a₂₅ a₂₆ a₂₇ ]
[ a₃₁ a₃₂ a₃₃ a₃₄ a₃₅ a₃₆ a₃₇ ]
Each column extends vertically through all rows.
For example, Column 1 contains:
- a11 from Row 1
- a21 from Row 2
- a31 from Row 3
This gives 3 elements in Column 1.
The same pattern applies to all 7 columns in the matrix.
The number of elements in each column equals the number of rows.
Since A has 3 rows, each column contains 3 elements.
Therefore, each column of A contains 3 elements.