Given that the cubical piece has side (s) 7 mm, and a cylindrical hole of diameter (d) as 3 mm.
The volume of the piece can be calculated as,

It is mentioned that the material costs $207 per cubic meter, so the cost (c) of 1 piece is calculated as,

This is the cost (in dollars) for 1 piece.
Given that the manufacturer wants to produce 1,000,000 such pieces, so the total cost (TC) is calculated as,

Thus, the total prototypes will cost around $60.75
Correlation coefficient is always between -1 and +1. So it cannot be +2.3
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Answer:
3 times x = 16
Step-by-step explanation:
He needs 3 1/4 more yards of fabric because 5.5 - 2.25 = 3.25