Answer :
Somewhere in a table of trig-function definitions that you have somewhere,
it mentions that
tan(a) = sin(a) / cos(a).
So it must follow that
tan(A) = (0.500) / (0.866) = 0.577 (rounded)
it mentions that
tan(a) = sin(a) / cos(a).
So it must follow that
tan(A) = (0.500) / (0.866) = 0.577 (rounded)