"Tiangong-1" is my country's first target aircraft, and its approximate circular flight orbit has a radius of about 7,000 kilometers. "Tiangong-1" flies about tens of thousands of kilometers around the orbit.
"天宫一号"是我国第一个目标飞行器，其近似圆形飞行轨道的半径约为0.7万千米．"天宫一号"绕轨道一圈约飞行多少万千米．
<gadget id="calculator">2 * 3.14 * 0.7</gadget>
<output>4.396</output>

<result>4.396</result>