There is a cylindrical glass, the measured inner diameter is 8 cm, and the depth of the liquid medicine inside is 6 cm. At this time, the volume of the liquid medicine is 4/5 of the capacity of the glass. How much liquid medicine can be added to fill the glass?
有一只圆柱体的玻璃杯，测得内直径是8厘米，内装药水的深度是6厘米，这时的药水体积是杯子容量的(4/5)，问再加多少药水可以把杯子注满？
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16 * 6</gadget>
<output>301.44</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">301.44 / (4/5)</gadget>
<output>376.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">376.8 * (1/5)</gadget>
<output>75.36</output>

<result>75.36</result>