By definition, the number
is the ratio between the circumference and the diameter:

This implies that

And so your circumference is 
Answer: 4(3x +5) or 2(6x +20)
Step-by-step explanation:
Answer: just use photomath
Step-by-step explanation:
Answer:
V = π × r² × h
Step-by-step explanation:
All you need to do is multiply the base times the height and since the base is a circle whose formula is π × r², we get π × r² × h.