Math question, please help

==========================================================
Explanation:
Let's say that a = 25, b = 37 and c = 32 are the side lengths.
The uppercase letters A,B,C are opposite their lowercase counterparts.
That means angle A is opposite side a = 25
Apply the law of cosines to find angle A
a^2 = b^2 + c^2 - 2*b*c*cos(A)
25^2 = 37^2 + 32^2 - 2*37*32*cos(A)
625 = 1369 + 1024 - 2368*cos(A)
625 = 2393 - 2368*cos(A)
625 - 2393 = -2368*cos(A)
-1768 = -2368*cos(A)
-2368*cos(A) = -1768
cos(A)= (-1768)/(-2368)
cos(A) = 0.746621621621622
A = arccos(0.746621621621622)
A = 41.7014263373247
A = 41.7