Help with 3D spur gear drawing (no tooth width given) !!

[Nlevismith95]

As the title states, I am trying my best to create this drawing for my AutoCAD class,  but I am having no luck due to missing information and my lack of skills. This is the first module where we are covering 3D modeling so the textbook has been no help other than basic commands. What I am most frustrated with is not having the tooth width. I have started by drawing the diameters of the circles. Then I drew a line from center to outside most circle quadrant. From there I used polar array on the line with 60 items to hopefully get the tooth width or a way of drawing the arcs, but I am having no luck. I realize I am probably going about this wrong, so any help would be much appreciated. The lack of information in this class has been very frustrating for a beginner like myself. In what situation would I not have the tooth width when drawing? Why do I have to derive information when I'm just learning the software.... Anywho, please help me before I go insane. Thanks!!!!