Answer:
2.195%
Step-by-step explanation:
Assuming that both planets are a sphere, we have to:
26590 * 28% = 7445.2
7445.2 miles would be the diameter of the moon, now to calculate the volume, we know that the radius is half the diameter, so:
r2 = d2 / 2 = 7445.2 / 2 = 3722.6
and the radius of the planet would be:
r1 = d1 / 2 = 26590/2 = 13295
now the volume of the planet we know is equal to:
v1 = 4/3 * pi * r1 ^ 3
and the volume of the moon would be:
v2 = 4/3 * pi * r2 ^ 3
We want to calculate the percentage by volume, therefore:
v2 / v1 = 4/3 * pi * r2 ^ 3 / 4/3 * pi * r1 ^ 3
v2 / v1 = 3722.6 ^ 3/13295 ^ 3
v2 / v1 = 0.021952
that is, the volume of the moon represents 2.195%