From the Super Mario Wiki
The Protractor

The Protractor is a souvenir located in the Doodads folder in WarioWare: Twisted! The Protractor displays an angle (from a total of 360°) based on how much the console is tilted. Unlike the other doodads, it looks strikingly different than a regular protractor, sporting a futuristic look instead. It is used in order to measure angles. If A Button is pressed, the displayed angle is reset back to 0°.