After drawing a parallelogram with four sides of 5 cm into a square, the area increases by 7.5 cm2. What is the height of the original parallelogram in cm?
把一个四边都是5厘米的平行四边形拉成一个正方形后，面积增加了7.5平方厘米，原来平行四边形的高是多少厘米．
<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">25 - 7.5</gadget>
<output>17.5</output>

<gadget id="calculator">17.5 / 5</gadget>
<output>3.5</output>

<result>3.5</result>