Answer:
A) 39
B) 900
C) 60%
A) proportion:
21.84 is 56% of x number
x number = 100%
If you want to calculate x you can use proportion. First of all make this kind of system..
x - 100%
21.84 - 56%
Then multiply numbers diagonally.
56x = 2184
Finally solve x
x = 2184/56
x = 39