Geo - Rt triangle

This topic has expert replies
User avatar
Master | Next Rank: 500 Posts
Posts: 447
Joined: Sun Apr 22, 2012 7:13 am
Thanked: 46 times
Followed by:13 members
GMAT Score:700

Geo - Rt triangle

by hemant_rajput » Thu Jul 04, 2013 9:58 am
The perimeter of a certain isosceles right triangle is 32 + 32 2√. What is the length of the hypotenuse of the triangle?
(A)16
(B)32
(C)8 root(3)
(D)8 root(2)
(E)16 root(2)
I'm no expert, just trying to work on my skills. If I've made any mistakes please bear with me.
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Thu Jul 04, 2013 10:16 am
hemant_rajput wrote:The perimeter of a certain isosceles right triangle is 32 + 32 √2. What is the length of the hypotenuse of the triangle?
(A)16
(B)32
(C)8 root(3)
(D)8 root(2)
(E)16 root(2)
EDIT: I deleted my post. I had assumed that the question was identical to this popular question:
https://www.beatthegmat.com/relation-bet ... tml#700804

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Wed Nov 06, 2013 6:54 am, edited 1 time in total.
Brent Hanneson - Creator of GMATPrepNow.com
Image

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Thu Jul 04, 2013 10:34 am
hemant_rajput wrote:The perimeter of a certain isosceles right triangle is 32 + 32 √2. What is the length of the hypotenuse of the triangle?
(A)16
(B)32
(C)8 root(3)
(D)8 root(2)
(E)16 root(2)
EDIT: I deleted my post. I had assumed that the question was identical to this popular question:
https://www.beatthegmat.com/relation-bet ... tml#700804

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Wed Nov 06, 2013 6:55 am, edited 1 time in total.
Brent Hanneson - Creator of GMATPrepNow.com
Image

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Thu Jul 04, 2013 10:37 am
hemant_rajput wrote:The perimeter of a certain isosceles right triangle is 32 + 32√2. What is the length of the hypotenuse of the triangle?

(A)16
(B)32
(C)8 root(3)
(D)8 root(2)
(E)16 root(2)
The sides of an isosceles right triangle are proportioned: s : s : s√2.
So if s=side and h=hypotenuse, then h = s√2 and s = h/√2.

We can plug in the answers, which represent the hypotenuse.
The correct answer is unlikely to be C, since √3 is not a value typically attributed to an isosceles right triangle.

Answer choice D: h = 8√2
s = (8√2)/√2 = 8.
p = 8 + 8 + 8√2 = 16 + 8√2.
Eliminate D. The perimeter needs to be quite a bit larger.

Answer choice B: h = 32
s = 32/√2 = (32*√2)/(√2*√2) = (32√2)/2 = 16√2.
p = 16√2 + 16√2 + 32 = 32 + 32√2. Success!

The correct answer is B.
Last edited by GMATGuruNY on Thu Jul 18, 2013 2:13 am, edited 1 time in total.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Junior | Next Rank: 30 Posts
Posts: 17
Joined: Tue Apr 09, 2013 9:00 pm
GMAT Score:700

by kuzzden » Wed Jul 10, 2013 12:31 am
Hi, maybe simple algebraic method will also help:

Since the triangle is isosceles, its P = 2x + y
since it is right y*y = 2x*x, since all values are positive
x= y / sqr(2) = y*sqr(2)/2

Finally, after substitution we get P = y + y* sqr(2) = 32 + 32*sqr(2)
So, y = 32
The best way to make your dreams come true is to wake up!

User avatar
Senior | Next Rank: 100 Posts
Posts: 90
Joined: Wed Jun 26, 2013 10:55 pm
Thanked: 11 times
Followed by:1 members

by macattack » Thu Jul 18, 2013 1:22 am
Hi experts,
you gave two dissimilar answers!!!! I think Mitch got it right!
Cheers