The volume of the cone increases by [[$ 80 \% $]]. By ow many percent (at the accuracy of one percent) does the cone's

a) radius change?

Answer: The radius of the cone changes by [[$ \% $]].

b) height change?

Answer: The height of the cone changes by [[$ \% $]].

c) area change?

Answer: The area of the cone changes by [[$ \% $]].