Find the volume of the composite space figure to the right to the nearest while number

the volume of the figure is cm.3

Consider a cube that has sides of length l. now consider putting the largest sphere you can inside this cube without any point on the sphere lying outside of the cube. the volume ratio -volume of the sphere/ volume of the cube is 1. 5.2 × 10−1 2. 3.8 × 10−1 3. 1.9 4. 2.5 × 10−1 5. 3.8

The anwser cause i do not understand just plez

Felix wrote several equations and determined that only one of the equations has no solution. which of these equations has no solution?