求助!一題數學圓形數
回答 (2)
✔ 最佳答案
39度.
Let CBE be x
CBE=CEB
CEB=x
EBD=90(semi-circle)
180-EBD-CBE=ABD
180-90-x=ABD
90-x=ABD
BCE=180-CBE-CEB=180-2X
BCE=ADB
ADB=180-2X
ADB+ABD+27=180
180-2x+180-90-x+27=180
-3x=-117
x=39
Since DE is a diameter,
∠EBD=90˚
∴∠DBA=90˚-27˚
=63˚
∠CBE+90˚+∠DBA=180˚( adj. ∠s on st.line)
∠CBE=180˚-90˚-63˚
= 27˚
參考: MYSELF
收錄日期: 2021-04-29 18:14:39
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