If the length of a rectangle is reduced by 4 cm, the area is reduced by 60 square centimeters, and the figure after reduction is exactly a square. So, what is the area of the original rectangle?
一个长方形，如果长减少4厘米，面积就减少了60平方厘米，减少后的图形正好是一个正方形，那么，原来长方形面积是多少？
<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">15 + 4</gadget>
<output>19</output>

<gadget id="calculator">19 * 15</gadget>
<output>285</output>

<result>285</result>