Help me with #3 please

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

Aflower has 26 chromosomes. to create a new flower, how many would a sperm cell have what is called?

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