What is the perimeter of 4 isosceles right triangles with sides 5dm assembled into a rectangle?
直角边为5dm的4个等腰直角三角形拼成长方形，周长是多少
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>