35% packed their lunch. 65/100 bought hot lunch. 100-65=35.
Answer:
A. change in a dependent variable
I don't know where the angle β is, so I will make the assumption that tanβ = h/r

V volume = 60
r radius = 2
h = r tanβ
-24.3 feet
-22.55-19.5 is -42.05
-42.05+ 17.75 is -24.3