## Rangpur Higher Secondary 2011/6

Problem for Higher Secondary Group from Divisional Mathematical Olympiad will be solved here.
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BdMO
Posts: 134
Joined: Tue Jan 18, 2011 1:31 pm

### Rangpur Higher Secondary 2011/6

Problem 6:
2010_rang.png (23.15 KiB) Viewed 4870 times
In the figure $AB = 12$ is the diameter of the circle. $MN||AB$ and $\angle BAN = 15^{\circ}$. Find the length of the arc $MN$.

Mehfuj Zahir
Posts: 78
Joined: Thu Jan 20, 2011 10:46 am

### Re: Rangpur Higher Secondary 2011/6

Let the centre is O.Connect O,N.ON=OA.Angle OAN=angleONA=15.AB is parallel to MN.Then angle ANM=15.SO that
angleONM=angleOMN=30.So angleMON=120.Then the length of the arc MN is (120/360).2.pi.6=4pi

Tahmid Hasan
Posts: 665
Joined: Thu Dec 09, 2010 5:34 pm

### Re: Rangpur Higher Secondary 2011/6

yes it's $4 \pi$
বড় ভালবাসি তোমায়,মা

Dipan
Posts: 158
Joined: Wed Dec 08, 2010 5:36 pm

### Re: Rangpur Higher Secondary 2011/6

arc MN is (120/360).2.pi.6=4pi[/quote]

is it a generalized formula????/please explain it.

Dipan
Posts: 158
Joined: Wed Dec 08, 2010 5:36 pm

### Re: Rangpur Higher Secondary 2011/6

Mehfuj Zahir wrote:.Then the length of the arc MN is (120/360).2.pi.6=4pi

is it a generalized formula??please someone explain it.

Shifat
Posts: 53
Joined: Sun Jul 31, 2011 12:21 pm