Describe the formation of ridges and mountains

There are several different ways that mountains (and ridges) can form. ... Mountain ridges are a result of either tectonic forces or erosional forces. Many mountains were formed as a result of Earth's tectonic plates converging or diverging or slipping past one another.

if he does not use open the compass the a width greater than half of po, he will not be able to find the midpoint of the line, without the midpoint of the line, he will not be able to bisect the line.   to find the midpoint of a line the circles drawn with a compass must either intersect or be touching.