In the figure above, AC passes through the center of the square ABCD,

Question

https://gmatclub.com/forum/download/file.php?id=49741 In the figure above, AC passes through the center of the square ABCD, and CE is perpendicular to AC. What is the minimum number of degrees the square must be rotated so that BC will be parallel to EC? A. 45 B. 90 C. 135 D. 180 E. 270 image977.png

LeoN88 · Answer

AC being diagonal bisects angle BCD into 45 degrees each.

So, we have to rotate 45 degrees (say arm BC) along point B, so that BC ll EC'

BjornMattsson · Answer

I don't understand this question, if we twist the square 45 degrees to the right the lines will be perpendicular. 45 degrees to the right and they will touch, and hence by definition not be parallel?

Would be grateful if someone could ellaborate a little and point out where I'm wrong!

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LeoN88 · Answer

Focus on this statement- "What is the minimum number of degrees the square must be rotated so"

So, you have to assume that the lines will be parallel after the operation.

Now, by what minimum degrees we must tilt the line to achieve the objective (parallel).

Once you get questions like this in GMAT don't focus on "if we twist the square 45 degrees to the right"; you have to make it parallel and what is the least degree measurement to achieve it.

ScottTargetTestPrep · Answer

Since AC passes through the center of the square, it bisects angle BCD, making angle BCE = 45 degrees. If we rotate the square 45 degrees counterclockwise, BC will be parallel to EC.

Answer: A

Kinshook · Answer

Given: In the figure above, AC passes through the center of the square ABCD, and CE is perpendicular to AC.

Asked: What is the minimum number of degrees the square must be rotated so that BC will be parallel to EC?

Angle ACB =Angle BCE = 45

IMO A

Posted from my mobile device

In the figure above, AC passes through the center of the square ABCD,

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In the figure above, AC passes through the center of the square ABCD,

Prep Toolkit

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