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#1 2007-07-03 06:48:19

Prakash Panneer
Member
Registered: 2006-06-01
Posts: 110

Clock Problem

if the length of the hour and minute hand of a clock are 3 cm and 8 cm respectively. What is the distance in cm, between the tips of the hands at 2 O' clock?

Thanks in Advance!


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#2 2007-07-03 06:55:37

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Clock Problem

At two o’clock, the angle between the hour hand and the minute hand is 60°. Now apply the cosine rule and you should be able to work out the answer. (It’s 7 cm.)

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#3 2007-07-03 10:11:18

John E. Franklin
Member
Registered: 2005-08-29
Posts: 3,588

Re: Clock Problem

3^2 is 9
8^2 is 64
3*8 is 24
For sixty degrees, the cosine is one-half or 0.5
So the 2 in the cosine rule goes away and turns into a one.
So 9 + 64 is 73 and 73 - 24 is 49, so what times what is 49?
That is the answer.
But there are other ways to do this problem, if want to know, ask.


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