Third time asking. I N E E D H E L P

29: 81.5

30: 9

31: 180

Step-by-step explanation:

29: if c=9 then squared then it is 9 times 9 which equals 81 then a equals 1/2 which is 0.5 in fraction so we add 81 + 0.5 =81.5

30: c equals 9 which we times by 2 and equals 18 then we times 18 by a which is 0.5 and it goes back down to 9

31: b equal 15 and it is squared so we times 15 by 15 which equals 225 and then we multiply 5 times c and c is 9 so 5 times 9 is 45 and 225 minus 45 equals 180

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.