Look at the equation you have for the side again. Setting x=0 gives you but setting y=0 does givesI calculated the distances of the side and base of the triangle by finding the intercepts of the tangent.
Heres what I got: side = (a^2 + 4)/2 and base = a^2 + 4
For the second question, you have and you want to be maximum. So sub in , diffrentiate to get what x you have, and work back to get the area( hint, the x and the y are going to be the same)