In a fan-shaped statistical graph, it indicates that the number of myopic students in a certain grade is 45% of the total number of students, what is the central angle of the fan-shaped circle that indicates the number of myopic students?
在一个扇形统计图中，表示某年级学生近视人数是学生总数的45%，则表示学生近视人数的扇形圆心角是多少．
<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">360 * (9/20)</gadget>
<output>162</output>

<result>162</result>