alonesofar
幼苗
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是圆台吧,
补充为圆锥,设上面小圆锥体高h,母线长l,整个圆锥高=h+800,母线长L:
h:h+800=250:520
520h=250h+800x250
270h=800x250
h=800x250/270=20000/27
l²=h²+(250/2)²=(20000/27)²+125²=564321.8450
l=√564321.8450=751.2136
侧面展开的扇形弧长=直径xπ=250π=785.3975;
圆心角α:360°=扇形弧长:以l为半径的圆的周长
α=250πx360°/(2xlxπ)=125x360°/751.2136=59.9031°;
大扇形弧长=520π=1633.6268;
边长是什么?圆台侧面母线长?(=L-l)
L²=(h+800)²+(520/2)²=1540.7407²+260²=2441482.0302
L=√2441482.0302=1562.5242
L-l=1562.5242-751.2136=811.3106;
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alonesofar
大扇形半径=整个圆锥的母线长L=1562.5242; 小扇形半径=上面小圆锥的母线长l=751.2136;