Let, height of the tower be x metre. So, tan 45 = (x-40)/(diff. between the feet of building & tower). Thus, diff. between their feet = (x-40) metre [since, tan 45 =1]. Again, tan 60 = x/(x-40) . Or, rt3*(x-40) = x . Or, x(rt3 - 1) = 40*rt3 . Or, x*0.732 = 40*1.732 . Thus, x = 94.64 (approx) . Hence, height of the tower is 94.64 m Ans.