Sorry this is a late response, I have just got done taking it myself. The answer is 3/5. You have 40 and 32, so you try figuring out (since you're simplifying) the LOWEST common multiple in this case. Since you always put the smallest number (the ones given to you which in this case is 32) as the numerator, the largest [is 40] making it the denominator. Apparently, the answer is 3/5. I argue that because there is no number between these two that three goes into, since the smallest that goes into 32 is 4. If they'd fix the answer, it'd be 4/5. Other than that, put down 3/5.
Side AC is opposite angle B because it is the furthest you can get on the triangle to be away from point B. This segment is a leg of the right triangle. Note how the letter B is not anywhere to be found in AC.
angle D is the right angle, the side across from this right angle is the hypotenuse EF
with reference angle F, we have opposite = ED = 4 adjacent = DF = 3