On a map with a scale of 1:30000. A triangular fish pond has a base of 5 cm and a height of 4 cm. What is the actual area of this fish pond?
在一幅比例尺是1：30000的地图上．量的一块三角形的鱼塘的底是5厘米，高是4厘米．这个鱼塘的实际面积是多少？
<gadget id="calculator">1 / 30_000</gadget>
<output>1/30_000 = around 0.000033</output>

<gadget id="calculator">5 / (1/30_000) / 100</gadget>
<output>1_500</output>

<gadget id="calculator">4 / (1/30_000) / 100 / 10_000</gadget>
<output>3/25 = around 0.12</output>

<gadget id="calculator">1_500 * (3/25)</gadget>
<output>180</output>

<result>180</result>