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亮亮想用一块铁皮制作一个圆锥模型,要求圆锥的母线长为12cm,底面圆的半径为5c...
亮亮想用一块铁皮制作一个圆锥模型,要求圆锥的母线长为12cm,底面圆的半径为5cm.那么,这个圆锥模型的侧面展开扇形铁皮的圆心角度数应为( )
A.90°
B.120°
C.150°
D.240°
考点分析:
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