Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
2 arctan (0.28 / (2 * D)) = 2 arctan (0.24 / (2 * (D - d))); solve for d
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random