muting's centroid

this are the pictures of centroid that i make with Janet in July 20, 2007. first we have to draw a scalene triangle on a patty paper, to draw a centroid we have to find out the medians and the midpoints, not the vertex, so we can find the centroid. then we copy it down on a cardboard and cut the triangle out. next we place the centroid on a pencil eraser tip and try to balance it. when we see it balance because of the center of gravity make it balance. next we place the centroid on the length of the pencil. this one we have to place it with the longer median, not the shorter median, but this one we have to use some of proportion because it is hard to balance.