Algebra 2, matrices help

Question

If matrix C is a 5 X 2 matrix and D is a 2 X 1 matrix, what are the dimensions of C•D?

Answer 1

Matrix C: 5 X 2

Matrix D: 2 X 1

When multiplying matrices, you have to make sure that the number of columns in the first matrix is equal to the number of rows in the second matrix. For this problem, Matrix C has 2 columns and Matrix D has 2 rows. When multiplying the two, the resulting matrix has dimensions of the numbers that aren't identical. For reference:

Matrix W has dimensions A X B and

Matrix V has dimensions B X C

W * V has dimensions A X C

Therefore, the answer is

C * D = 5 X 1