Gina willson all about algebra (TRIANGKE ANGLE SUM) HELP ASAP!!

The trigonometric ratios sine and secant are reciprocals of each other

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

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !