The centroid of a triangle is 2/3 of the way from the vertex to the opposite side. The centroid is the intersection of the medians. Each median has as endpoints a vertex and the midpoint of the opposite side.
a.
PC is 2/3 of PY, and CY is 1/3 of PY.
If CY = 10, then PC = 20, and PY = 30
b.
If QC = 10, then ZC = 5, a nd ZQ = 15.
c.
X is the midpoint of side PQ.
PX = XQ = 1/2(PQ)
If PX = 20, PQ = 40