It is currently 19 Mar 2018, 11:36

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# PS - Geometry

Author Message
Manager
Joined: 24 Sep 2008
Posts: 185
Schools: MIT / INSEAD / IIM - ABC

### Show Tags

06 Nov 2008, 08:31
1
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

PS - Geometry
Attachments

File comment: PS - Geometry

PS_Geometry.JPG [ 56.27 KiB | Viewed 1001 times ]

Intern
Joined: 04 Nov 2008
Posts: 15

### Show Tags

06 Nov 2008, 09:25
the answer is ( B )

40 * SQRT(3)

becase we have 2 type of geometry.

1) 6 rectangulars with area = 6*[2R * 2R/SQRT(3)] = 24 * SQRT(3)
2) 2 hexa with area = 2 * [ 6(1/2 * R * 2R/SQRT(3))] = 16 * SQRT(3)

Sum = 40 * SQRT(3)

( B )
SVP
Joined: 29 Aug 2007
Posts: 2457

### Show Tags

06 Nov 2008, 09:40
abohassan wrote:
the answer is ( B )

40 * SQRT(3)

becase we have 2 type of geometry.

1) 6 rectangulars with area = 6*[2R * 2R/SQRT(3)] = 24 * SQRT(3)
2) 2 hexa with area = 2 * [ 6(1/2 * R * 2R/SQRT(3))] = 16 * SQRT(3)

Sum = 40 * SQRT(3)
( B )

1) 6 rectangulars with area = 6*[2R * 2R/SQRT(3)] = 32 * SQRT(3)
2) 2 hexa with area = 2 * [ 6(1/2 * R * 2R/SQRT(3))] = 16 * SQRT(3)

Sum = 48 * SQRT(3)

( A )
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Current Student
Joined: 28 Dec 2004
Posts: 3317
Location: New York City
Schools: Wharton'11 HBS'12

### Show Tags

06 Nov 2008, 09:55
i have no clue on this question, can someone please explain why 6 rectangles? 2 Hex??

i was going with the approach that the ball is a sphere and as such its surface area is 4pir^2

so surface area of ball=16pi
SVP
Joined: 29 Aug 2007
Posts: 2457

### Show Tags

06 Nov 2008, 10:04
Hope visualization might help, hoever I could not get a picture for solid hexagon better than this one.
Attachments

Solid Hexagon.jpg [ 29.87 KiB | Viewed 956 times ]

_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

SVP
Joined: 17 Jun 2008
Posts: 1507

### Show Tags

07 Nov 2008, 05:55
Draw a regular hexagon and a circle inside it such that the circle touches the opposite sides (since the question is asking for the minimum surface area of the box, diameter of the circular ball should be the same as the distance between two opposite sides of the hexagon.

Now, half of diameter is 2 and since the center of the circle and two adjacant edges of hexagon form an equilaterl triangle, the side of the square = 4/sqrt(3).
Also, since we are talking of the minimum surface area, height of the box should be the same as the diameter of the ball.

Hence, total surface area (of course outside surface area) = 6 sides * 4/sqrt3 * 4 (height of box) = 32 * sqrt(3).
additionally, top and bottom surfaces of the hexagon will have area = 2 (top and bottom) * 6 (equlateral triangles in a hexagon) * 1/2 * 2 * 4/sqrt(3) = 16 * sqrt(3).

Hence, total area = 48 * sqrt(3).
Re: PS - Geometry   [#permalink] 07 Nov 2008, 05:55
Display posts from previous: Sort by