Original: If a line segment intersects two straight lines forming two interior angles on the same side that sum to less than two right angles , then the two lines , if extended indefinitely , meet on that side on which the angles sum to less than two right angles .
Simplified: if you cut a line segment with two lines , and the two interior angles the lines form add up to less than two right angles , then the two lines will eventually meet if you extend them long enough .