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Re: if BD=DA, wath is angle BAO [#permalink]
18 Apr 2011, 21:12

I believe all not drawn to scale problems are DS. You can trust your eyes if any PS geometry appears and somehow you are not able to solve it. you eyeball some options by merely looking at the shape or size. This may not be the best of allies but considering the time crunch it is.

ravsg wrote:

the dia says, "not drawn to scale" so guesswork may not work and there should be a mathematical way to arrive at the ans, if at all.

Re: if BD=DA, wath is angle BAO [#permalink]
18 Apr 2011, 21:25

gmat1220 wrote:

I believe all not drawn to scale problems are DS. You can trust your eyes if any PS geometry appears and somehow you are not able to solve it. you eyeball some options by merely looking at the shape or size. This may not be the best of allies but considering the time crunch it is.

ravsg wrote:

the dia says, "not drawn to scale" so guesswork may not work and there should be a mathematical way to arrive at the ans, if at all.

Posted from my mobile device

Posted from my mobile device

You are absolutely right about the time factor but here one has all the time one wants!
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Re: if BD=DA, wath is angle BAO [#permalink]
18 Apr 2011, 21:48

my solution : OB=OD because those are circle's radius; if BAO=A, then: A=B2; D1=B1; D1+D2=180; B2+A=D1 ==> B2+B2=B1 ==>2B2=B1 B1+B2=90 ;because BA is a tangent at B point 3B2=90 ==>B2=30==>A=30==>BAO=30 AM I WRONG???

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Re: if BD=DA, wath is angle BAO [#permalink]
18 Apr 2011, 21:52

annmary wrote:

my solution : OB=OD because those are circle's radius; if BAO=A, then: A=B2; D1=B1; D1+D2=180; B2+A=D1 ==> B2+B2=B1 ==>2B2=B1 B1+B2=90 ;because BA is a tangent at B point 3B2=90 ==>B2=30==>A=30==>BAO=30 AM I WRONG???

Looks good to me, I used the same to find out that 30 wasn't one of the choices.
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