How it works ?
If you select the RightTriangle tool (far right), simply plot 2 points. Then, enter in the measure of any acute angle. (You can also, if you choose, enter ∝ = name of slider) if you wish to quickly change the size of this acute angle.
BEST WAY to use this resource is to go to the 3 dots (upper right corner) and select OPEN IN APP. This will create a duplicate of this resource that you can freely use in the GeoGebra Classic app.