Can add PPI Calculator?

the Pythagorean calculator does half the work, but need to change input fields to “Pixels X” and “Pixels Y” or similar input fields, and a 3rd input field – diagonal LCD measurement, to divide the Pythagorean result by… here is an example of the formula

https://www.ehow.com/how_7794090_calculate-pixel-density.html

I took a look at the code, but couldn’t figure out where the actual calculations were performed.

https://www.ads-software.com/extend/plugins/calculatorpro-calculators/