Geometry

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Geometry

by RiyaR » Mon Jul 21, 2014 9:18 am
PQR is anisosceles triangle such that PQ=PR. Side QP is produced to a point S such that PS+PQ. Find angle QRS

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by GMATinsight » Mon Jul 21, 2014 10:04 am
RiyaR wrote:PQR is an isosceles triangle such that PQ=PR. Side QP is produced to a point S such that PS=PQ. Find angle QRS
Please find the answer below



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by [email protected] » Mon Jul 21, 2014 1:44 pm
Hi RiyaR,

This question can also be solved by TESTing VALUES. You do have to remember a few Geometry rules though:

1) The 3 angles in a triangle add up to 180 degrees
2) The angles on a line add up to 180 degrees
3) Isosceles triangles have 2 base angles that are equal

Using the above picture, try this...

1) Pick a value for angle Y. Remember that you're dealing with a triangle, so pick a number that will be easy to work with.
2) Figure out the third angle at the top of that smaller triangle.
3) Figure out the other angle on that line.
4) Figure out angle X (remember that this is another isosceles triangle)
5) Add up X + Y.

Final Answer: 90

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by Brent@GMATPrepNow » Mon Jul 21, 2014 8:34 pm
RiyaR wrote:PQR is anisosceles triangle such that PQ=PR. Side QP is produced to a point S such that PS+PQ. Find angle QRS
I'm not so crazy about the wording of this question. Side QP is produced?

What's the source of this question? Also, what are the 5 answer choices?

Cheers,
Brent
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by RiyaR » Tue Jul 22, 2014 6:18 pm
Hey thanks for the solution! The mistake I made was I tried to derive the answer by giving the angles values as "x".