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What is the perimeter of quadrilateral ABCD?

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What is the perimeter of quadrilateral ABCD?

by AAPL » Fri Dec 15, 2017 3:52 pm
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In the figure above, AD || BC. What is the perimeter of quadrilateral ABCD?

A. 590
B. 600
C. 620
D. 640
E. 680

In this PS question, I can complete a rectangle drawingn a parallel line to AB but starting in C, then I can determinate the longitude of the segment between D and E (new point in the interception between AD line and CE line) because I have a right triangle and using the Pitagoras's theorem I can determinate DE side. Once I do that I can get the perimeter of quadrilateral.

Experts, is correct my analysis? Can you assist me with this PS question please? Thanks!
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by GMATWisdom » Sat Dec 16, 2017 7:24 am
AAPL wrote:Image

In the figure above, AD || BC. What is the perimeter of quadrilateral ABCD?

A. 590
B. 600
C. 620
D. 640
E. 680

In this PS question, I can complete a rectangle drawingn a parallel line to AB but starting in C, then I can determinate the longitude of the segment between D and E (new point in the interception between AD line and CE line) because I have a right triangle and using the Pitagoras's theorem I can determinate DE side. Once I do that I can get the perimeter of quadrilateral.

Experts, is correct my analysis? Can you assist me with this PS question please? Thanks!
YES YOU ARE CORRECT
BY PYTHAGORUS THEOREM SIDE DE MUST DE 30.
THEREFORE PERIMETER =40+250+50+AE+ED=340+250+30=620
HENCE OPTION C
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by [email protected] » Sat Dec 16, 2017 11:39 am
Hi AAPL,

Yes - your approach is perfect. As a general rule, any time a GMAT question involves a shape OTHER than a triangle, rectangle, square or circle, you should look to break that shape into 'pieces' that are typical (re: a rectangle, triangle(s), etc.). In some questions, you'll have to break a common shape into two other common shapes (for example, a square can be broken into two 45/45/90 triangles and an equilateral triangle can be split into two 30/60/90 triangles). In the broad sense, this is really just about re-organizing information that you're given so that you can answer the question that is asked - and THAT is an aspect of most Quant (and Verbal) questions.

GMAT assassins aren't born, they're made,
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