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#1 2006-02-21 05:26:06

zaara
Guest

sector

A circular sector of radius 15cm and angle 160 degrees is bent in such a way that it forms a hollow cone where the straight sides of the sector meet without overlapping.

How do I find the semi-vertical angle of the cone?

Thanks! :-)

#2 2006-02-21 13:18:46

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,565

Re: sector

I made one out of paper and it appears to be about 22 degrees or half of a 45.
The whole angle appears to be about 45 degrees.  I assume you want half of that.


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#3 2006-02-21 13:24:32

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,565

Re: sector

26.3878 degrees


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#4 2006-02-21 13:45:37

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,565

Re: sector

I suggest making one out of paper and labelling highlighting the dimensions that
you know or can derive.  This experiment will be very fun.    If you don't have
a protractor, you can use a watch or clock and the 160 degrees is approximately
from 3.333333 minutes to 30 minutes using the arc of a minute hand.


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