The diameter of the outlet of a toothpaste is 5mm. Xiao Ming squeezes out 15mm of toothpaste every time he brushes his teeth, so this toothpaste can be used 72 times. The toothpaste of this brand was changed to a new package with the net content unchanged, and the diameter of the outlet was changed to 6mm. Xiao Ming also squeezed out 15mm of toothpaste each time according to the habit. After changing the new package, how many times can this toothpaste be used?
一支牙膏出口处直径为5mm，小明每次刷牙都挤出15mm长的牙膏，这样这只牙膏可用72次．该品牌牙膏在净含量不变的情况下改换新包装，将出口处直径改为6mm，小明还按习惯每次挤出15mm长的牙膏，换了新包装后，这支牙膏能用多少次？
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) ** 2</gadget>
<output>25/4 = around 6.25</output>

<gadget id="calculator">3.14 * (25/4) * 15 * 72</gadget>
<output>21_195</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 15</gadget>
<output>423.9</output>

<gadget id="calculator">21_195 / 423.9</gadget>
<output>50</output>

<result>50</result>