A plane figure is enclosed by 10 line segments, what is the sum of all interior angles of this plane figure?
一个平面图形是由10条线段围成的，这个平面图形所有内角的和是多少°
<gadget id="calculator">10 - 2</gadget>
<output>8</output>

<gadget id="calculator">8 * 180</gadget>
<output>1_440</output>

<result>1_440</result>