radius angle

例句：

1. 1.The radius of the circle is 10 units.
   这个圆的半径是10单位。
2. 2. The radius of the Earth's orbit around the sun is about 6,378 kilometers.
   地球围绕太阳的轨道半径大约为6,378公里。
3. 3. The radius of the planet Mercury is less than that of Venus.
   冥王星的半径小于金星。