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655-705 Level|   Geometry|      
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The figure above is a cube. What is the measure of angle BEG 18 Jan 2012, 11:39
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C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

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46% (01:02) correct 54% (01:15) wrong based on 1258 sessions

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The figure above is a cube. What is the measure of angle BEG (not shown)?

A. 30°
B. 45°
C. 60°
D. 75°
E. 90°


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Cube.jpg [ 21.46 KiB | Viewed 32767 times ]
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C
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The figure above is a cube. What is the measure of angle BEG 18 Jan 2012, 11:47
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The figure above is a cube. What is the measure of angle BEG (not shown)?

A. 30°
B. 45°
C. 60°
D. 75°
E. 90°
Show more

Note that triangle BEG is equilateral: it's made by the diagonals of the adjacent faces of the given cube (and as faces of a cube are squares its diagonals are equal). Thus angle BEG=60 degrees.

Answer: C.
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The figure above is a cube. What is the measure of angle BEG 26 Mar 2012, 07:32
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htbreme

Hi everyone,
I wanted to make you a quick and apparently easy question that it's giving me a hard time:

What is the angle formed by the diagonals of to perpendicular faces of a cube?

I know the answer but I can't visualize why that's the answer

Source: local GMAT course

Thanks in advance
Show more

Added a question about this issue for a better understating.

Attachment:
Cube.jpg
Cube.jpg [ 30.11 KiB | Viewed 33734 times ]
The figure above is a cube. What is the measure of angle BEG (not shown)?
A. 30°
B. 45°
C. 60°
D. 75°
E. 90°

Note that triangle BEG is equilateral: it's made by the diagonals of the adjacent faces of the given cube (and as faces of a cube are squares its diagonals are equal). Thus angle BEG=60 degrees.

Answer: C.

Hope it helps.
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The figure above is a cube. What is the measure of angle BEG Updated on: 11 Mar 2018, 11:11
Originally posted by htbreme on 26 Mar 2012, 06:25.
Last edited by Bunuel on 11 Mar 2018, 11:11, edited 3 times in total.
Added a question, diagram and OA
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Attachment:
Cube - Q.jpg
Cube - Q.jpg [ 21.46 KiB | Viewed 31587 times ]
The figure above is a cube. What is the measure of angle BEG (not shown)?
A. 30°
B. 45°
C. 60°
D. 75°
E. 90°

Hi everyone,
I wanted to make you a quick and apparently easy question that it's giving me a hard time:

What is the angle formed by the diagonals of to perpendicular faces of a cube?

I know the answer but I can't visualize why that's the answer

Source: local GMAT course

Thanks in advance
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The figure above is a cube. What is the measure of angle BEG 31 Mar 2012, 11:16
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Bunuel
htbreme

Hi everyone,
I wanted to make you a quick and apparently easy question that it's giving me a hard time:

What is the angle formed by the diagonals of to perpendicular faces of a cube?

I know the answer but I can't visualize why that's the answer

Source: local GMAT course

Thanks in advance

Added a question about this issue for a better understating.

Attachment:
Cube.jpg
The figure above is a cube. What is the measure of angle BEG (not shown)?
A. 30°
B. 45°
C. 60°
D. 75°
E. 90°

Note that triangle BEG is equilateral: it's made by the diagonals of the adjacent faces of the given cube (and as faces of a cube are squares its diagonals are equal). Thus angle BEG=60 degrees.

Answer: C.

Hope it helps.
Show more

Why isn't it 90? Since two diagonals bisect two 90 degree angles would the x angle equal to 90? I understand your explanation, but would like to understand why my thinking is wrong? Thank you.
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The figure above is a cube. What is the measure of angle BEG 31 Mar 2012, 12:12
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htbreme

Hi everyone,
I wanted to make you a quick and apparently easy question that it's giving me a hard time:

What is the angle formed by the diagonals of to perpendicular faces of a cube?

I know the answer but I can't visualize why that's the answer

Source: local GMAT course

Thanks in advance

Added a question about this issue for a better understating.

Attachment:
The attachment Cube.jpg is no longer available
The figure above is a cube. What is the measure of angle BEG (not shown)?
A. 30°
B. 45°
C. 60°
D. 75°
E. 90°

Note that triangle BEG is equilateral: it's made by the diagonals of the adjacent faces of the given cube (and as faces of a cube are squares its diagonals are equal). Thus angle BEG=60 degrees.

Answer: C.

Hope it helps.

Why isn't it 90? Since two diagonals bisect two 90 degree angles would the x angle equal to 90? I understand your explanation, but would like to understand why my thinking is wrong? Thank you.
Show more

It would be correct for 2-D geometry, meaning the angle between two diagonals below is indeed 90 degrees:
Attachment:
Squares.png
Squares.png [ 2.5 KiB | Viewed 30441 times ]
But in 3-D geometry 2 faces are already 90 degrees to each other thus their diagonals would not form 90 degrees any more.

Hope it's clear.
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The figure above is a cube. What is the measure of angle BEG 05 Nov 2016, 02:35
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I don't understand this question. Where is there a triangle/an angle for BEG?

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The figure above is a cube. What is the measure of angle BEG 05 Nov 2016, 02:44
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gillyelephant
I don't understand this question. Where is there a triangle/an angle for BEG?

Posted from my mobile device
Show more



Note that triangle BEG is equilateral: it's made by the diagonals of the adjacent faces of the given cube (and as faces of a cube are squares its diagonals are equal). Thus angle BEG=60 degrees.
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The figure above is a cube. What is the measure of angle BEG 05 Nov 2016, 04:51
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Attachment:
The attachment Cube.jpg is no longer available
The figure above is a cube. What is the measure of angle BEG (not shown)?
A. 30°
B. 45°
C. 60°
D. 75°
E. 90°
Show more


Please find the solution as attached
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File comment: www.GMATinsight.com
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The figure above is a cube. What is the measure of angle BEG 07 Nov 2016, 17:19
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Baten80
Attachment:
Cube.jpg
The figure above is a cube. What is the measure of angle BEG (not shown)?
A. 30°
B. 45°
C. 60°
D. 75°
E. 90°
Show more

Since our given figure is a cube, we must recall that a cube is made up of 6 squares, which of course have all equal sides. We need to determine the measure of angle BEG. Let’s draw that angle in a diagram:



From our diagram we can see that we can actually create a triangle using angle BEG with sides BE, EG, and GB. Notice that each side is the diagonal of a square face of the cube and thus is equal in length. Therefore, we know that triangle BEG is an equilateral triangle and furthermore that angle BEG is 60 degrees.

Answer: C
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The figure above is a cube. What is the measure of angle BEG 09 Jun 2022, 13:07
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Easier to visualize if you consider GDB angle so that the telescoped perspective doesn't throw you off.

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The figure above is a cube. What is the measure of angle BEG 30 Jun 2023, 11:44
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