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.
5 * 1/2 * (4/sin(36 deg)) * (4/sin(36 deg)) * sin(72 deg)
5 * 1/2 * (4/sin(36 deg)) * (4/sin(36 deg)) * sin(72 deg)
Natural Language
Math Input
Extended Keyboard