Can someone with these few questions i have? ! itd they are attached : ) extra points!

Three cylinders have a volume of 2836 cm^3. cylinder a has a height of 900 cm. cylinder b has a height of 225 cm. cylinder c has a height of 100 cm. find the radius of each cylinder. use 3.14 as an approximate for π

What is the least common factor of 6 and 8

We just started the introduction into circles and i have no idea how to do this.