Be it a tree of which we seek its height. We place a stick at a random point in the ground. We locate such a point
on the ground where from the top of the stick we can aim the top of the tree. Due to the creation of similar triangles, the following is in effect: As many times the distance from us to the tree is greater than that of us to the stick, so many times is the tree taller than our stick. This method can be applied without locating the point on the ground but with the use of two uneven sticks.