If pq + qr = pr, how can you describe the points on line pr?

Acircle has a circumference of 28.36 units what is the diameter of the circle

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

Need so much on this one how many yards?