Picture: http://postimg.org/image/hgy8u7ig5/
A circular skating area is to be decorated with fencing around the circumference.
Minor arc AB of length 20m represents a prizing platform.
Show that the audience at the major arc AB will have the same view angle to the
platform and find the angle.
What is the question asking for?
F.5 Mathematics Circle
2014-10-19 11:24 pm
回答 (1)
2014-10-20 10:26 pm
✔ 最佳答案
This question is asking about the angle subtended to the centre of circle is twice the angle subtended to the circumference of circle.Let C be the position of audience on the major arc AB,
angle AOB = 2 x angle ACB
angle ACB = (1/2) angle AOB
angle AOB = 360 degree - 300 degree = 60 degree
Therefore,
angle ACB = (1/2) angle AOB = (1/2) 60 degree = 30 degree
The audience at the major arc AB will always have the same view angle of 30 degree to the platform.
收錄日期: 2021-04-11 20:53:11
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20141019000051KK00089