Okay the way you find out if a pair of ratios are equal is you would divide the denominator and nominator with each other, so: 13/7 and 9/4. But sense the answer would be in decimal form and cant be simplified this wouldnt be considered equivalent. Also if you divide 7 by 4 you get a different answer than when you do 13 divided 9.
You have to find a common denominator 1st then add. So 16 is the common denominator the problem should be 2 7/16+1 14/16+8-16= 3 29/16 then you need to divide 29/16 you will have 4 13/16
If you started at W and went all the way around the circle until you wound up back at W, you will have gone 360 degrees. Since the angle measurement that prevents that is 85 degrees, the answer must be 360 - 85 = 275.