Geometry question

Expert replies

sivanhas: Newbie | Next Rank: 10 Posts; Posts: 3; Joined: Tue Apr 23, 2013 3:10 am

by sivanhas » Wed Apr 24, 2013 10:01 pm

A parallelogram with area of 18 has a side of 6. Which of the
following could be one of its inside angles?
A. 30 B. 50 C. 60 D. 70

Does anyone has an idea how to solve this?

Like this post

Source: Beat The GMAT — Problem Solving | Wed Apr 24, 2013 10:01 pm

GMAT/MBA Expert

Anju@Gurome: GMAT Instructor; Posts: 511; Joined: Wed Aug 11, 2010 9:47 amFollowed by: 86 members; Location: Delhi, India; Thanked: 344 times

by Anju@Gurome » Wed Apr 24, 2013 10:22 pm

sivanhas wrote:A parallelogram with area of 18 has a side of 6. Which of the following could be one of its inside angles?

The area of a parallelogram with base B and height H (the perpendicular distance between base and the opposite side) is given by B*H

In this case, if we take B = 6, then H = 18/6 = 3

Now, we can draw different parallelograms with B = 6 and H = 3 as follows,

As we can see without changing B and H we can draw different parallelograms with different inside angles ranging from 0 to 180 degrees, excluding both.
For example, in the diagram,
Green ---> 30 degrees
Blue ---> 50 degrees
Red ---> 60 degrees

So, all the options are possible.

Anju Agarwal
Quant Expert, Gurome

Backup Methods : General guide on plugging, estimation etc.
Wavy Curve Method : Solving complex inequalities in a matter of seconds.

Â§ GMAT with Gurome Â§ Admissions with Gurome Â§ Career Advising with Gurome Â§

Like this post

rohankamath619: Newbie | Next Rank: 10 Posts; Posts: 4; Joined: Sun Sep 26, 2010 6:44 pmFollowed by: 1 member

by rohankamath619 » Thu Apr 25, 2013 6:12 am

Hi Anju,

By all options, do you mean 70 is also possible?

Thanks!

Like this post

GMAT/MBA Expert

Anju@Gurome: GMAT Instructor; Posts: 511; Joined: Wed Aug 11, 2010 9:47 amFollowed by: 86 members; Location: Delhi, India; Thanked: 344 times

by Anju@Gurome » Thu Apr 25, 2013 6:19 am

rohankamath619 wrote:By all options, do you mean 70 is also possible?

Yes, as I've mentioned "we can draw different parallelograms with different inside angles ranging from 0 to 180 degrees, excluding both". That means the inside angle can have any value greater than 0 and less than 180 degrees.

Hope that helps.

Like this post

fifafreak: Junior | Next Rank: 30 Posts; Posts: 15; Joined: Wed Jan 27, 2010 3:47 am; Thanked: 2 times

by fifafreak » Mon Apr 29, 2013 5:51 am

sivanhas wrote:A parallelogram with area of 18 has a side of 6. Which of the
following could be one of its inside angles?
A. 30 B. 50 C. 60 D. 70

Does anyone has an idea how to solve this?

Area of a parallelogram = a*b*sin(X) = 6*b*sin(X) = 18 => b*sin(X)= 3.

if X = 30; b = 6
if X = 60; b = 2_/3
if X = 90; b = 3 [for X=50, 6>b>2_/3 ; for X=70, 2_/3>b>3] ... so X can have any of the above values.

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review