There is a right triangle, the two sides of which are two prime numbers, and the sum is 12cm, what is the area of this right triangle in square centimeters?
有一个直角三角形，两条直角边是两个质数，和为12cm，这个直角三角形的面积是多少平方厘米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 5 * 7</gadget>
<output>35/2 = around 17.5</output>

<result>35/2 = around 17.5</result>