Tan(A) = opposite / adjacent if we call opposite "a" and adjacent "b" tan(A) = a/b then... tan(B) = b/a because it's on the other angle so "b" is now opposite angle B and "a" is adjacent.
So really you just need to take the reciprocal of the given values.
6. tan(A) = 1.25 reciprocal is flipping the value and using it to divide by 1.
you can keep as decimal , 1/1.25 = 0.8 or change to fraction 1.25 = 5/4