This question is a piece-o-cake if you know the formulas for the area and volume of a sphere, and impossible of you don't.
Area of a sphere = 4 π R² (just happens to be the area of 4 great circles)
Volume of a sphere = (4/3) π R³
We know the area of this sphere's great circle, so we can use the first formula to find the sphere's radius. Then, once we know the radius, we can use the second formula to find its volume.
Area of 4 great circles = 4 π R²
Area of ONE great circle = π R²
225 π cm² = π R²
R² = 225 cm²
R = √225cm² = 15 cm .
Now we have a number for R, so off we go to the formula for volume.
Volume = (4/3) π R³
= (4/3) π (15 cm)³
= (4/3) π (3,375 cm³)
= 14,137.17 cm³ (rounded)
This answer feels very good UNTIL you look at the choices. _____________________________________________________
I've gone around several loops and twists trying to find out what gives here, but have come up dry.
The only thing I found is the possibility of a misprint in the question:
If the area of a great circle is 225π cm², then the sphere's AREA is 900π cm².
I'm sure this is not the discrepancy. I'll leave my solution here, and hope someone else can find why I'm so mismatched with the choices.
