I have an array of values

Patching Crack Seal Chip Seal Overlay Rebuild Treatment
803.7 133.95 5036.52 21432 53580 Chip Seal
2160.99 360.165 13542.2 57626.4 144066 Crack Seal
76.53 12.755 479.588 2040.8 5102 Rebuild

Total maintenance cost =sum(???)

What I want is to look up the value of treatment in the specific row and use
the value in the sum function. In the example above the first row, Chip
Seal, would return 5036.52; the second row, Crack Seal, would return 360.165;
and the final row, Rebuild, would return 5102; these values would be used in
the calculation of the sum to give a total of $10498.69 How can I accomplish
this?