Inverse Variation Calculator

Enter a table of x and y pairs with question marks where values are missing, and this finds the constant of variation, fills every gap and draws the curve through the points. It also tests the table rather than assuming it: if the products disagree by more than the spread you allow, it says so and gives the size of the disagreement instead of quietly fitting a line. The inverse square and inverse cube forms are there too, for light, sound and gravity. A second tab takes a single known pair and one new value and solves for the other, with the direct variation answer beside it for comparison.