First you need to convert them to the same unit. 1 cm is 10 mm, so the scale is 5:10. 5*2 is 10, so the scale factor is 2.
Answer: 
Required theorem:
Pythagorean theorem = 
In other words, one side length squared + another side length squared = the middle lined squared.
Step-by-step explanation:

We can only have a positive distance so your final answer is :

Answer:
V=65.94 in^3 (inches cubed)
Step-by-step explanation:
V=πr^2h/3
h = 7
r = 3
V = (3.14)(3^2)(7/3)
V= (3.14)(9)(2.333)
V=65.94 in^3