red right-angled triangle with a hypotenuse of 18 cm, a blue right-angled triangle with a hypotenuse of 45 cm, and a yellow square can form a large right-angled triangle, then the red and blue What is the sum of the areas of a right triangle in square centimetres?
用一张斜边长18厘米的红色直角三角形纸片、一张斜边长45厘米的蓝色直角三角形纸片与一张黄色正方形纸片正好可以拼成一个大直角三角形，则红色与蓝色直角三角形的面积和是多少平方厘米．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">45 * 9</gadget>
<output>405</output>

<result>405</result>