precalc

The easy one first     Tan A = opp / adj =  24/ 36 = 2/3       so it is eather answer  A  or D

 

Now find the hypotenuse length by pythagorean theorem

24²  + 36² = h²

h = sqrt 1872  =  12 sqrt 13

 

Sin A = opp/ hyp =   24 / (12 sqrt13) =  2 / sqrt13  = 2 sqrt13/13      so the answer is A

    as a check, see if you can calculate the cosine A = adj/hyp   to see if it matches the answer !