A)
Adb=z
ABD=y
ADB=2x+y=180
x+y+z=180
x+180-2x+z=180
-x+z=0
x=z--(1)
isosceles triangle !! side opp to Z AD=6 similary BD=6
and now 2x and 2x are equal there BC=6
A) angle doesnt help in any ways
its neother 45:45:90 / 30:60:90
IMO A
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ronniecoleman
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it seems i have gone blindsparsh.21 wrote:
Please explain...
thanks
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vittalgmat
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here is another way to solve this:
It uses the rule:
The exterior angle of a triangle = sum of the other 2 interior angles.
So from the figure
BDC = ABD + BAD
So ABD = x. There for Triangle ABD is isoscles.
Stmt 1 says AD = 6
So AD = BD = 6
Triangle BDC is isoscles coz base angles 2x and 2x.
So BC = BD = 6.
Sufficient.
Stmt 2. : we cannot find length of any side from just the angles alone.
So A
It uses the rule:
The exterior angle of a triangle = sum of the other 2 interior angles.
So from the figure
BDC = ABD + BAD
So ABD = x. There for Triangle ABD is isoscles.
Stmt 1 says AD = 6
So AD = BD = 6
Triangle BDC is isoscles coz base angles 2x and 2x.
So BC = BD = 6.
Sufficient.
Stmt 2. : we cannot find length of any side from just the angles alone.
So A
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vittalgmat
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