Target Test Prep 20% Off Flash Sale is on! Code: FLASH20

Redeem
Target Test Prep
5-Day Free Trial
5-day free, full-access trial TTP

Available with Beat the GMAT members only code

MORE DETAILS
Target Test Prep
Magoosh
Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

MORE DETAILS
Magoosh

triangle in xy plane

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 435
Joined: Wed Nov 16, 2011 7:27 am
Thanked: 48 times
Followed by:16 members

triangle in xy plane

by alex.gellatly » Tue Jun 05, 2012 6:19 am
In the xy-plane, the vertices of a triangle have coordinates {0,0},{3,3}, and {7,0}. What is the perimeter of the triangle?

A. 13
B. srt34
C srt43
D 7+6srt2
E 12+3srt2

[spoiler]I got 10srt58, which is not in the ans choice. I got this by noticing it's a right triangle with side a=7, b=3, and then finding side c = srt58. Is this a bad question or am I way off track?[/spoiler]

Thanks...
Top
User avatar
MBA Admissions Consultant
Posts: 2279
Joined: Fri Nov 11, 2011 7:51 am
Location: New York
Thanked: 660 times
Followed by:266 members
GMAT Score:770

by Jim@StratusPrep » Tue Jun 05, 2012 9:12 am
This is not a right triangle. Let's give each point a label

A = (0,0)
B = (3,3)
C = (7,0)

AB = 3sqrt2 found via a 45-45-90 triangle
AC = 7 simply the length on the X-axis
BC = 5 If you drop an altitude from (3,3) you will for a 3-4-5 right triangle with the hypotenuse equal to BC

Answer = 12 + 3sqrt2

Also, once you get the 3sqrt2 there is only 1 answer that includes it --- D
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Tue Jun 05, 2012 7:45 pm
alex.gellatly wrote:In the xy-plane, the vertices of a triangle have coordinates {0,0},{3,3}, and {7,0}. What is the perimeter of the triangle?

A. 13
B. srt34
C srt43
D 7+6srt2
E 12+3srt2

[spoiler]I got 10srt58, which is not in the ans choice. I got this by noticing it's a right triangle with side a=7, b=3, and then finding side c = srt58. Is this a bad question or am I way off track?[/spoiler]

Thanks...
Distance between (0, 0) and (3, 3) = √[(3-0)^2 + (3-0)^2] = √18
Distance between (0, 0) and (7, 0) = √[(7-0)^2 + (0-0)^2] = √49 = 7
Distance between (3, 3) and (7, 0) = √[(7-3)^2 + (0-3)^2] = √(16+9) = 5
Perimeter of triangle = 5 + 7 + √18 = [spoiler]12 + 3√2[/spoiler]

The correct answer is E.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
GMAT Instructor
Posts: 2630
Joined: Wed Sep 12, 2012 3:32 pm
Location: East Bay all the way
Thanked: 625 times
Followed by:119 members
GMAT Score:780

by Matt@VeritasPrep » Thu Mar 17, 2016 9:11 pm
Jim@StratusPrep wrote: Also, once you get the 3sqrt2 there is only 1 answer that includes it --- D
There are two (D and E), and D is wrong.

Another approach to the problem is here.
Top
Post new topic Post Reply
• Page 1 of 1