AEB is an equilateral triangle with each side equal to 10cm. A semicircle with the diameter AB is drawn and cuts EA and EB at D and C respectively. Find the shaded area.
Trigonometric Functions
2007-06-17 3:39 am
回答 (2)
2007-06-17 5:30 pm
✔ 最佳答案
cut AC角ACB=90 & 角ABC=60
cosABC(60)=BC/AB=1/2
BC=5cm
ADO BCO DCO都是等邊三角形
其面積和=5x2.5√3X3/2
=32.4cm^2
the shaded area
=10X5√3/2-32.4
=10.9CM^2
2007-06-17 3:53 am
首先計左個semicircle既area先
10除2 X 3.14
之後計個triangle既area
張個triangle分開一半
用tan黎計
3個角係60度
因為係equilateral triangle
跟住再計個EDC既area
係60/360 X (10除2)二次方
跟住咪用最大個個數去減其如個兩個數
因為我黎到睇唔到有shade area
如果個shade area係AD同CB就好似我頭先咁計
如果個shade area係AD同C同EDC
上面個到就唔洗計EDC個part既area
就係咁簡單
10除2 X 3.14
之後計個triangle既area
張個triangle分開一半
用tan黎計
3個角係60度
因為係equilateral triangle
跟住再計個EDC既area
係60/360 X (10除2)二次方
跟住咪用最大個個數去減其如個兩個數
因為我黎到睇唔到有shade area
如果個shade area係AD同CB就好似我頭先咁計
如果個shade area係AD同C同EDC
上面個到就唔洗計EDC個part既area
就係咁簡單
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