A section of line is placed on circle A, and the central angle of the formed arc is exactly 270°. Circle B is surrounded by this section of line. If the radius of circle A is 10 cm, what is the radius of circle B?
一段线放在圆A上，构成的弧所对的圆心角恰为270°，用这段线围成圆B若圆A的半径为10厘米，那么圆B的半径有多大？
<gadget id="calculator">270 * 3.14 * 10</gadget>
<output>8_478</output>

<gadget id="calculator">8_478 / 180</gadget>
<output>471/10 = around 47.1</output>

<gadget id="calculator">(471/10) / 2 / 3.14</gadget>
<output>7.5</output>

<result>7.5</result>