Use a piece of rectangular red paper with a length of 100 cm and a width of 80 cm to make some small triangular flags whose right angles are 5 cm and 4 cm respectively. How many sides can you make at most?
用一张长100厘米，宽80厘米的长方形红纸，做一些直角边分别是5厘米和4厘米的三角形小旗，最多能做多少面？
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">20 * 20 * 2</gadget>
<output>800</output>

<result>800</result>