Hi, I am having trouble with this problem. My Geometry text book explains how to do this, but not very well, and I have come to a problem on a practice test that is nothing like what's in the book. I would really appriciate some help with this please!

*Figure is a right triangle

Question: Given the Figure below (right triangle), find ,

a if sin B = 0.42, cos B = 0.91, tan B = 0.47 and c =60

Thank you very very much!