The area of a classroom is a rectangle. Its width is 6.2 meters, and its length is 2.15 meters more than its width. How big is this classroom?
一间教室的面积是长方形．它的宽是6.2米，长比宽多2.15米，这间教室的面积有多大？
<gadget id="calculator">6.2 + 2.15</gadget>
<output>8.35</output>

<gadget id="calculator">8.35 * 6.2</gadget>
<output>51.77</output>

<result>51.77</result>