The volume and height of a cylinder and a cone are equal respectively. It is known that the radius of the base of the cylinder is 9cm. What is the area of the base of the cone?
一个圆柱与一个圆锥的体积和高分别相等，已知圆柱的底面半径是9cm，圆锥的底面积是多少？
<gadget id="calculator">9 ** 2</gadget>
<output>81</output>

<gadget id="calculator">3.14 * 81 * 3</gadget>
<output>763.02</output>

<result>763.02</result>