Question

7.7 cm

Answer 1

Step-by-step explanation:

I guess the 3.14 is to be used for pi (and not r, which is what we need to find out).

the volume of a cylinder is ground area × height.

the ground area is the area of a circle, which is pi×r².

so, we have

pi×r²×height = 115 cm³

3.14×r²×7.7 = 115 cm³

3.14×r² = 14.93506494...

r² = 4.756390107...

r = 2.18091497... cm