## data:
x <- matrix(c(8,24,5,22,10,25,4,21,13,28),nrow=2)

## squared euclidean distances:
xd <- dist(t(x))^2


x1 <- x <- matrix(c(8,24,4.5,21.5,10,25,13,28),nrow=2)
xd1 <- dist(t(x1))^2
## clustering:
xc <- hclust(xd, method="centroid")

## plot of dendrogram:
plot(xc)
## heights:
xc$height