Menelaus's theorem

Menelaus's theorem is like a math puzzle. It says that if you draw three lines (called "sides") that meet at some point (called a "corner") then the ratio between the two lines on the outside (the "opposite sides") will always be the same as the ratio of the three pieces of the line on the inside (the "adjacent sides"). To put it simply, if you have three lines that meet together like a triangle, the ratios of the sides will always stay the same no matter what.