Somebody want to help me real quick???

[Neatfish]

It's 5/8inch but how did they figure that out?

 

[Neatfish]

Guess I just hate math so much I can't figure it out or get it in my head.

 

[ManEatingShrimp]

I think the washer is 1" total diameter and each side is 3/16" thick.
3/16"+3/16"=6/16"
1"-6/16"=10/16
10/16"=5/8"

 

[Neatfish]

The professor had to show everybody in class how to work out that problem. Pretty sure I failed my math test and will need to re-take it good thing you get a second try after 30mins tutoring.