explanation- so the opposite of a positive is a negative, the opposite of a negative is a positive. so it is the same for this. for example 10/7 is positive so you make it a negative for it be the opposite.
i would help with the rest, but it is hard when you have to label things on a diagram when you are doing it on a computer like this. sorry!
384 in^{3}. because if you have to add the bases together then so 7+5=12 then you times the width and height together so 4*8=32. Then you times 12 * 32 = 384.
Yes it is because if you round 14 to 15, and add 15 and 15 you get 30. Then do 30 times 3 to get 90. Round this to the nearest hundred and you get 100.