picture: http://i986.photobucket.com/albums/ae342/silver_so/001.jpg
In the figure, OAB is a sector of radius r and arc length l, and CDE is a triangle of height r and base length l. Prove that the area of sector OAB is equal to the area of triangle CDE.
F2 Math question
2010-07-26 9:18 pm
回答 (3)
2010-07-26 9:58 pm
2010-07-26 11:08 pm
2010-07-26 9:55 pm
L=2(pi)rx(theta/360)
L.=(theta)(pi)(r)/180
__________________
Area of triangle:
(((theta)(pi)(r)/180)*(r))/2
((theta)(pi)(r^2)/180)*(1/2)
((theta)(pi)(r^2)/360
______________
Area of circle:
(pi)r^2*(theta/360)
(theta)(pi)(r^2)/360
_______________________
Their areas are same
2010-07-26 13:57:28 補充：
http://hk.knowledge.yahoo.com/question/question?qid=7010072300537
L.=(theta)(pi)(r)/180
__________________
Area of triangle:
(((theta)(pi)(r)/180)*(r))/2
((theta)(pi)(r^2)/180)*(1/2)
((theta)(pi)(r^2)/360
______________
Area of circle:
(pi)r^2*(theta/360)
(theta)(pi)(r^2)/360
_______________________
Their areas are same
2010-07-26 13:57:28 補充：
http://hk.knowledge.yahoo.com/question/question?qid=7010072300537
收錄日期: 2021-04-22 00:50:50
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100726000051KK02433