The base of a triangle is 5 meters long. If the base is reduced by 2 meters, the area of the triangle is reduced by 4 square meters. What is the original area of the triangle?
一个三角形的底长5米，如果底缩小2米，那么三角形的面积就减少4平方米，原来三角形的面积是多少．
<gadget id="calculator">2 / 2 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">5 * 4 * (1/2)</gadget>
<output>10</output>

<result>10</result>