We can compute the circular area with radius.
我们能用半径计算出圆的面积。
A flat-bottomed, roughly circular volcanic crater of explosive origin that is often filled with water.
小火山口一种底部平坦、大致呈圆形的火山爆发后形成的盛满水的低洼地
A device for protection from the weather consisting of a collapsible, usually circular canopy mounted on a central rod.
雨伞用来防风雨装置，由某在一根中心柱上的可折收的，经常是圆形的罩蓬构成
