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## Official Guide Explanation:Problem Solving #145

Background

This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Review (12th ed.). Click the links on the question number, difficulty level, and categories to find explanations for other problems.

These are the same explanations that are featured in my "Guides to the Official Guide" PDF booklets. However, because of the limitations of HTML and cross-browser compatibility, some mathematical concepts, such as fractions and roots, do not display as clearly online.

Question: 145
Page: 172
Difficulty: 6 (Moderately Difficult)
Category 1: Geometry > Quadrilaterals >
Category 2: Geometry > Triangles > Pythag
Category 3: Geometry > Triangles > Multiple figures

Explanation: The distance AB can be seen as the hypotenuse of a right triangle consisting of the bottom of the rudder and the right side, which measures 5 feet. Since AB =13, you should recognize that this is a common pythagorean ratio of 5:12:13. Without having to do the math, you can immediately determine that the bottom of the rudder is 12 feet. The area of a trapezoid is w(((h1 + h2)/2)), which in this case is 12(((5 + 2)/2)) = ((12(7))/2) = 6(7) = 42, choice (C).

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