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本帖最后由 Camello 于 2011-7-27 10:23 编辑
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依9#图
" f o/ ~& }5 n2 l. B; i扇形 = H1 + H2
5 z% Y5 T$ t" ~; S4 uH2 = 所求
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http://www.analyzemath.com/Geome ... th_area_sector.html
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<< 令 r = 1 >>
i4 x7 ?$ Y ^5 ?% b( T* J单位圆周长 = Pi * 28 o4 u a/ k/ A1 u
单位圆面积 = Pi * 1 * 1 = Pi% s, L1 Z- y, ?# q r( H8 |* w" h0 x' z
& J% Q- Y- y+ P; ?& i扇形面积 = (弧长 / 单位圆周长) * Pi% ?: f4 W* N+ Q3 W" s8 C( B% k
扇形面积 = Sarea = θ [(θ 弪度量) --> 半圆心角值]: ~' d3 S/ ~8 ?% |; H% Z
H1 = sinθ * consθ6 {" H* x' q4 _, W/ z8 y# Z* V
H2 = θ - sinθ*consθ4 a- ^( F) i$ \1 }( A
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5 v& A- ?0 b* C+ y五等分
7 C; V( I; x, t4 ?121.0739438696948$ ]# R+ {- a# @) V
六等分
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七等分7 T+ V. S- h# G9 S% @/ o
106.3947074651414
! X3 a/ U, [0 I% }4 G$ J4 v! P八等分
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