More Math: 歐式幾何第五定理證明

Prove that only 1 parallel line through a point outside a line exists.(parallel to the line)

My prove: draw a line through a point perpendicular to the horizontal line. 90 degree exists. only one line trough a point can be perpendicular to the vertical line.

證明只有一條平行線穿過一條線外的點。（與線平行） 我的證明：通過點畫一條垂直於水平線的線。 90度存在。通過一個點只有一條線可以垂直於垂直線。