The outer radius of a ring is 8cm, the inner radius is (3/4) of the outer radius, what is the area of the ring in cm**2.
一个圆环的外圆半径是8cm，内圆半径是外圆半径的(3/4)，圆环的面积是多少cm**2．
<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">3.14 * 64</gadget>
<output>200.96</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">8 * (3/4)</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36</gadget>
<output>113.04</output>

<gadget id="calculator">200.96 - 113.04</gadget>
<output>87.92</output>

<result>87.92</result>