A triangular scarf is 4 decimeters high and the bottom is three times the height. How many square decimeters of silk are needed to make 20 such triangular scarves?
一种三角形围巾，高4分米，底是高的3倍，做这样的三角形围巾20条，需要多少平方分米的丝绸？
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

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

<gadget id="calculator">12 * 2 * 20</gadget>
<output>480</output>

<result>480</result>