Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 02 Jul 2015, 15:32

### 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

# What is the area of the region enclosed by lines y=x y=-x

Author Message
TAGS:
CEO
Joined: 21 Jan 2007
Posts: 2760
Location: New York City
Followers: 9

Kudos [?]: 384 [0], given: 4

What is the area of the region enclosed by lines y=x y=-x [#permalink]  22 Oct 2007, 11:11
What is the area of the region enclosed by lines
y=x
y=-x
and the upper crescent of the circle y^2 + x^2 = 4?

pi/4
pi/2
3/4*pi
pi
4*pi
SVP
Joined: 01 May 2006
Posts: 1798
Followers: 8

Kudos [?]: 102 [0], given: 0

(D) for me

The line y=x is at 45° from the X axis. Similarly, y=-x gives also an angle of 45° with the Y axis.

So, the angle between y=x and y=-x is 90° (360°/4).

y^2 + x^2 = 4 = 2^2 represents a circle centered on 0(0,0) and with a radius of 2.

The 2 lines y=x and y=-x interestec on 0(0,0). So, the upper area described is actually 1/4 of the area of the circle definied before.

Thus, we have:
Area = 1/4 * Area of circle
= 1/4 * Pi * 2^2
= Pi
VP
Joined: 09 Jul 2007
Posts: 1108
Location: London
Followers: 6

Kudos [?]: 76 [0], given: 0

Re: Challenges - Coordinate Area [#permalink]  22 Oct 2007, 11:20
bmwhype2 wrote:
What is the area of the region enclosed by lines
y=x
y=-x
and the upper crescent of the circle y^2 + x^2 = 4?

pi/4
pi/2
3/4*pi
pi
4*pi

the circle: R=2 and with the centre at x and y=0
and if you draw it it is the 1/4 of the circle that we need to find the area.
so 1/4pi(r^2)=1/4pi*4=pi

D

hope some1 will draw the image
VP
Joined: 09 Jul 2007
Posts: 1108
Location: London
Followers: 6

Kudos [?]: 76 [0], given: 0

I decided to do a good thing in my life for you BMWhype
Attachments

forbmwhype4.JPG [ 11.04 KiB | Viewed 423 times ]

CEO
Joined: 21 Jan 2007
Posts: 2760
Location: New York City
Followers: 9

Kudos [?]: 384 [0], given: 4

Thanks. Did not realize it was so easy.

OA is D.
Similar topics Replies Last post
Similar
Topics:
What is the value of xy? 1. y=x+1 2.y=x^2 + 1 5 16 Mar 2008, 06:58
Line 2x + 3y = 6 and Line y-x=2 and the X axis enclose a 2 06 Nov 2007, 08:18
Point (1,0) is closest to which of the following lines? y=x 2 01 Nov 2007, 12:28
Is the point (a,b) on the line y=x? I)a=3 II)b=a-2 3 08 Sep 2006, 00:56
In xy-plane, what is the area of the region encircled by 1 06 May 2006, 04:23
Display posts from previous: Sort by