GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Dec 2018, 04:07

### 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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### Happy Christmas 20% Sale! Math Revolution All-In-One Products!

December 20, 2018

December 20, 2018

10:00 PM PST

11:00 PM PST

This is the most inexpensive and attractive price in the market. Get the course now!
• ### Key Strategies to Master GMAT SC

December 22, 2018

December 22, 2018

07:00 AM PST

09:00 AM PST

Attend this webinar to learn how to leverage Meaning and Logic to solve the most challenging Sentence Correction Questions.

# In the figure above, if O is the center of the circle, which of the fo

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 51280
In the figure above, if O is the center of the circle, which of the fo  [#permalink]

### Show Tags

11 Dec 2017, 22:08
00:00

Difficulty:

35% (medium)

Question Stats:

90% (01:17) correct 10% (02:46) wrong based on 36 sessions

### HideShow timer Statistics

In the figure above, if O is the center of the circle, which of the following points lies outside the circle?

(A) (–7, –8)
(B) (–7, 7)
(C) (8, –6)
(D) (8, 5)
(E) (9, 4)

Attachment:

2017-12-12_1001_002.png [ 7.87 KiB | Viewed 567 times ]

_________________
Senior SC Moderator
Joined: 22 May 2016
Posts: 2222
Re: In the figure above, if O is the center of the circle, which of the fo  [#permalink]

### Show Tags

12 Dec 2017, 08:09
Bunuel wrote:

In the figure above, if O is the center of the circle, which of the following points lies outside the circle?

(A) (–7, –8)
(B) (–7, 7)
(C) (8, –6)
(D) (8, 5)
(E) (9, 4)

Attachment:
2017-12-12_1001_002.png

One quick way to approach this question: add the squares of the coordinates in the answers. They should not be greater than 100. (I avoid the distance formula when there are less error-prone ways to solve.)

The general equation for a line is $$x^2 + y^2 = r^2$$.

This circle's radius is 10 (center x-coordinate is at 0, a point on the circle is (10,0), subtract x-coordinates).

So this line's equation is $$x^2 + y^2 = 100$$.

A point outside the circle will have coordinates whose squares sum to more than 100.

$$x^2 + y^2 = 100$$

(A) (–7, –8)
$$(-7)^2 + 8^2 = 49 + 64 = 113$$
Outside the circle. Keep

(B) (–7, 7)
$$49 + 49 = 98$$. Inside the circle. Reject

(C) (8, –6)
$$64 + 36 = 100$$. On the circle. Reject

(D) (8, 5)
$$64 + 25 = 89$$. Inside the circle. Reject

(E) (9, 4)
$$81 + 16 = 97$$. Inside the circle. Reject

Re: In the figure above, if O is the center of the circle, which of the fo &nbs [#permalink] 12 Dec 2017, 08:09
Display posts from previous: Sort by