Question 519551
Use the Law of Cosines:
{{{7^2 = 4^2 + 6^2 - 2*4*6*cos(C)}}}
cos(C) = -3/-48 = 1/16
C =~ 86 degs
------------
Find a 2nd angle the same way.
Then subtract the sum of those 2 from 180 to find the 3rd angle.