show that the four lines drawn from the vertices of any tetrahedron to the centroids of the opposite faces meet in a point which is at three-fourths of the distance from each vertex to the oppositefaces.
two circles with radii a and b respectively touch each other externally and a smaller circle with radius c touch both the circles and also the common tanjent to the two circles,then prove that:
{(1/a)^0.5} +{(1/b)^0.5} ={(1/c)^0.5}
Judith works after school at her family's tent company. One of their best selling tents is an A-frame tent that is 4 ft. high and has a rectangular bottom 4ft. wide by 6 ft. long. The sides of the tent are 4.5 ft. long. How much canvas is needed to make the tent?