Confusing easy math
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Raiyan Jamil
- Posts:138
- Joined:Fri Mar 29, 2013 3:49 pm
In a isosceles triangle ABC , AB = AC . D is a point on AB such that , AD = DC = BC . Then what is the value of angle A ?
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asif e elahi
- Posts:185
- Joined:Mon Aug 05, 2013 12:36 pm
- Location:Sylhet,Bangladesh
Re: Confusing easy math
$\angle CBA=\angle CBD=\angle CDB=\angle DAC+\angle DCA=2\angle CAD=2\angle BAC=2(180^{\circ}-2\angle CBA)$
So$ \angle CBA=72^{\circ}$
And $\angle A=180^{\circ}-2\angle CBA=36^{\circ}$
So$ \angle CBA=72^{\circ}$
And $\angle A=180^{\circ}-2\angle CBA=36^{\circ}$