When the moon was crescent shaped people began to disappear. 月亮开始呈月牙形的时候人们就开始失踪。
With the knowledge of Hindu trigonometric functions, two reconstructive methods, crescent and zone figure, were given by Bhaskara to prove the area formula of the sphere. 摘要婆什伽罗利用他所熟知的印度三角函数知识,给出了球表面积公式的两种证明方法,即月牙形方法和环带形方法。