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本帖最后由 Camello 于 2011-7-27 10:23 编辑 + H/ u: j# g( N. h2 T7 }. v
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依9#图
9 s' |- H* p1 l3 E( E扇形 = H1 + H2
/ n# r' O8 n( c& _" M3 d+ FH2 = 所求
+ m- ?+ Q0 I6 k. v0 xRef:* ]: X: o2 T/ w8 d+ ~
http://www.analyzemath.com/Geome ... th_area_sector.html, z1 G" L( q6 B' @
http://regentsprep.org/Regents/m ... 6/CircleSectors.htm. N4 w& W/ c2 \$ O% l
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<< 令 r = 1 >>
/ t' U# P& b2 F单位圆周长 = Pi * 2
+ |: \+ f9 E5 o单位圆面积 = Pi * 1 * 1 = Pi/ t1 o/ E' U% b" B* _* K
7 N" G; v( u! x4 M* ?5 U1 U) o扇形面积 = (弧长 / 单位圆周长) * Pi1 ~5 u+ f: d& H+ D- ~9 R
扇形面积 = Sarea = θ [(θ 弪度量) --> 半圆心角值]
- {; ?5 |- ~2 P6 P- m! B8 QH1 = sinθ * consθ9 L8 A3 P4 ~( T+ i6 s
H2 = θ - sinθ*consθ
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7 {! b4 _( i+ v0 N6 c2 \; X z- F2 T/ x+ `; _
五等分7 E+ ]" \; `4 E0 V" e8 v. E
121.0739438696948
4 k0 g& F5 Y I$ m/ d六等分' T* H; c/ {6 |
112.8135972435375
/ |4 {, w( v: H( r3 R" L七等分3 c4 `2 L! E6 m- I O
106.3947074651414
. i' O" ]% t! Q& \八等分& u! h0 j: i0 n J4 m: \5 z3 ^5 S
101.2038436062725
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