AB=AE=BE=10,
triangle AEB is equilateral triangle(等邊三角形)
find the shaded area.
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f.4 amaths
2007-12-24 11:07 pm
回答 (1)
2007-12-25 4:36 am
✔ 最佳答案
Note that ΔEDC, ΔDCO, ΔADO, ΔBCO are equilateral triangles and they are congruent to each other.Area of ΔEDC
= (1/2)(5)(5)sin(π/3)
= (25/2)[(√3)/2]
= (25√3)/4
Area of EDOC
= 2 x area of ΔEDC
= (2)[(25√3)/4]
= (25√3)/2
Area of sector DOC
= π(5)² (1/6)
= (25/6)π
Area of shaded region
= (25√3)/2 - (25/6)π
= 8.560665705...
≈ 8.56 (correct to 3 sig. fig.)
參考: My Maths knowledge
收錄日期: 2021-04-13 14:47:37
原文連結 [永久失效]:
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