If it was 25%, it would be a 90 degree angle. So we can calculate this using a proportion. 25/90 = 24/x. Cross multiply to get 25x = 2160. When you divide by 25 on both sides you get 86.4. So the angle should be 86 degrees. Hope this helps.
Number of people that chose salad = 81
Percentage of people that chose salad over meat dish = 27%
Let us assume the number of people on the survey = x
Then
27% * x = 81
(27/100) * x = 81
27x = 81 * 100
27x = 8100
x = 8100/27
= 300
So a total of 300 people participated in the survey.I hope the procedure is clear enough for you to understand. Based on this method you can always solve similar types of problems without requiring any kind of help from outside.
Decreased by 25%
find 25% of 12 and decrease 12 by it
percent means parts out of 100
25%=25/100=1/4
'of' means multiply
25% of 12=1/4 times 12=3
decrease 12 by 3
12-3=9
answer is 9