Okay, so YZ = 3 cm. You have XM correct. And YM = 0.5.
Now, you have the midpoint M at the correct spot.
Use Pythagorean's theorem o find the length of AB. a² + b² = c² a=6, b=8.
6² = 36 8² = 64 36 + 64 = 100 AB = 10!
If AB = 10 then AM = 5 MB also = 5
If B is the midpoint of AC, C would be 12 rows down from A, and 16 columns to the right. The last spot where the line intersects.
There are your answers!