Finding angles in 3D space 1

In the next applet, you can make different triangles visible in order to aid you calculate angles.
In the rectangular prism, what is the measure of each of the following angles:
[br][math]\angle AKD[/math][br][br][math]\angle KBL[/math][br][br][math]\angle MLC[/math]
– Paula Siberio

Information: Finding angles in 3D space 1