The lengths of the two sides of a right-angled triangle are 3cm and 4cm respectively. If the triangle is observed with a magnifying glass of 2 times, what is the area in square centimetres?
一直角三角形两直角边长分别为3cm和4cm，用2倍放大镜观察此三角形，其面积为多少平方厘米．
<gadget id="calculator">3 * 2 * 4 * 2</gadget>
<output>48</output>

<gadget id="calculator">48 / 2</gadget>
<output>24</output>

<result>24</result>