I don't see a diagram, but if the portion of the tennis region you are asked to analyze doesn't intersect anywhere else/any other regions pertaining to other sports, wouldn't the sport chosen by these students be solely tennis?
The answer is 43.6 your welcome 87.20 divided by two is 43.6.
For the first two, put it them over 100. So number 1 would be 34/100 or 17/50 reduced. Number 2 is 77.5/100 and since it is a decimal, I would keep it at over 100. Number 3 put 8/10 or 4/5 reduced and number 4 is different. Think of it as money and how a quarter is in relation to a dollar. You have 4 quarters in a dollar, so since you have .25%, it is 1/4.
This really is left up to you as long as you have an odd number in the tens place and a 7 in the ones place. How big (or small) the number is is up to you. As long as it is at least 17, it's pretty much up to you.