Your answer is 160. Sorry about that answer above I laughed reading it hahaha.
If we call the number "x" then:
x*25%=21
x*25/100=21
x=21*4
x=84
Answer:

Step-by-step explanation:
Curved surface area=
where R is radius and H is height
Since H=6R then curved surface area=
Therefore,
and making R the subject

Therefore, H=6R=6*3.000604=18.00362 m

Therefore, 
Answer:
Y=0.35x+18.99
Step-by-step explanation:
Y = total cost
X = number of letters
Do you have an example of what the "Constant of proportionality" would be for a different question?