Using SUMPRODUCT with TRANSPOSE

Question

I'm trying to use TRANSPOSE inside SUMPRODUCT. What's wrong with my formula?

I use Excel 2013 if that matters.

Answer 1

Your formula is correct, you just need to press Crtl+Shift+Enter to confirm it and make it an array formula. In some cases SUMPRODUCT will sometimes automatically handle array treatment of arguments, but a TRANSPOSE argument apparently is not among them.

Answer 2

I'm not sure what result you want but would be interested to know whether:

=MMULT(D9:F9,D3:D5)  

entered with Ctrl+Shift+Enter is such.