The lengths of the two sides of a right triangle are 30 cm and 40 cm respectively, and the length of the hypotenuse is 50 cm. What is the area of this triangle in square centimetres.
一个直角三角形的两条直角边长分别是30厘米和40厘米，斜边长50厘米．这个三角形的面积是多少平方厘米．
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<result>600</result>