Conditionally divide two arrays

Dear Forum,

I have the following issue. I would like to conditionally divide two arrays by one another and sum the result. In the example below, I want to divide row 2 by row 4 but only if the word in row 1 appears in row 3. Here, this yields: 1) divide cell A2 by B4 (because both have the mathcing word "word1") which gives 2 and divide cell C2 by C4 (both have the matching word "word3") which gives 3. 2) Sum the result which gives 5.

Thank you very much for your help! very appreaciated!
Best regards

	a	b	c	d	e	f
1	Word1	Word2	Word3	Word4	Word5	Word6
2	10	13	18	15	11	19
3	Word8	Word1	Word3	Word9
4	5	5	4	4