In order to alleviate traffic congestion, the Highway Bureau is widening Hope Road. The width of the road has been increased from 12 meters to 21 meters. How much is the increase?
为了缓解交通拥挤的状况，公路局正在对希望路进行拓宽改造．路宽由原来的12米增加到21米，拓宽了百分之几？
<gadget id="calculator">21 - 12</gadget>
<output>9</output>

<gadget id="calculator">9 / 12</gadget>
<output>3/4 = around 0.75</output>

<result>3/4 = around 0.75</result>