A cone is sawn into two equal parts along the diameter of the bottom surface. The area of the cut is 2.5cm**2. The diameter of the bottom surface of the cone is 5cm. What is the height?
一个圆锥沿底面直径把它锯成相等的两部份，截成的面积是2.5cm**2，圆锥的底面直径是5cm，高是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2.5 * (2/5)</gadget>
<output>1</output>

<result>1</result>