15. in triangle ∆pqr, c is the centroid.
a. if cy = 10, find pc and py
b. if qc = 10, find zc and zq
c. if px = 20, find pq

Because C is the centroid, therefore:

Segments PZ = ZR;  RY = YQ; QX = XP

A.
If CY = 10, then

PC = 2*CY = 20
PY = PC + CY = 20 + 10 = 30
     PC = 20      PY = 30

B.
If QC = 10, then

ZC = QC/2 = 5
ZQ = ZC + QC = 5 + 10 = 15
      ZC = 5        ZQ = 15

C.
If PX = 20
Because the median RX bisects side PQ, therefore PX = QX = 20
PQ = PX + QX = 40
     PQ = 40

you would need to know all the numbers that are on there

step-by-step explanation: