The height of a cylinder is equal to 4 times the radius of the base. The circumference of the side view of the cylinder is 61.68 cm. What is the radius of the base of the cylinder in cm?
一个圆柱的高等于底面半径的4倍，这个圆柱的侧面展开图的周长是61.68厘米，这个圆柱体底面半径是多少厘米．
<gadget id="calculator">61.68 / 20.56</gadget>
<output>3</output>

<result>3</result>