If B is the midpoint of AC, what is the length of BE? : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 22 Jan 2017, 17:55

### 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

# If B is the midpoint of AC, what is the length of BE?

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Senior Manager
Status: Do and Die!!
Joined: 15 Sep 2010
Posts: 326
Followers: 1

Kudos [?]: 432 [1] , given: 193

If B is the midpoint of AC, what is the length of BE? [#permalink]

### Show Tags

15 Nov 2010, 11:00
1
KUDOS
9
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

53% (01:49) correct 47% (01:03) wrong based on 260 sessions

### HideShow timer Statistics

Attachment:

geo.JPG [ 3.23 KiB | Viewed 2457 times ]
If B is the midpoint of AC, what is the length of BE?

(1) Angel BAE=30
(2) CD = $$\sqrt{20}$$
[Reveal] Spoiler: OA

_________________

I'm the Dumbest of All !!

Math Expert
Joined: 02 Sep 2009
Posts: 36601
Followers: 7097

Kudos [?]: 93476 [2] , given: 10563

### Show Tags

15 Nov 2010, 11:36
2
KUDOS
Expert's post
4
This post was
BOOKMARKED
shrive555 wrote:
If B is the midpoint of AC, what is the length of BE?

(1) Angel BAE=30
(2) CD = $$\sqrt{20}$$

why 1 isn't enough ?

As angle E=Angle D then BE||CD. Now as B is the midpoint of AC and BE||CD then BE becomes a midsegment (a line segment joining the midpoints of two sides of a triangle). The property of midsegemnt: the midsegment is always half the length of the third side. So 2BE=CD.

(1) Angel BAE=30 --> triangles BAE and CAD are 30-60-90 triangles where BE is a midsegment. We know only angles but not the lengths, so can not find BE. Not sufficient.

(2) $$CD= \sqrt{20}$$ --> as 2BE=CD then $$BE=\frac{CD}{2}=\sqrt{5}$$. Sufficient.

Check triangles chapter of Math Book for more on this topic: math-triangles-87197.html

Hope it helps.
_________________
Senior Manager
Status: Do and Die!!
Joined: 15 Sep 2010
Posts: 326
Followers: 1

Kudos [?]: 432 [0], given: 193

### Show Tags

15 Nov 2010, 11:48
Thanks B, Well i was thinking that we know about 30,60,90 as 1:/sqr3:2 ..... But these are ratios of sides only NOT the lengths.
_________________

I'm the Dumbest of All !!

Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7125
Location: Pune, India
Followers: 2139

Kudos [?]: 13697 [1] , given: 222

### Show Tags

16 Nov 2010, 19:12
1
KUDOS
Expert's post
shrive555 wrote:
If B is the midpoint of AC, what is the length of BE?

(1) Angel BAE=30
(2) CD = $$\sqrt{20}$$

why 1 isn't enough ?

Triangles ABE and ACD are similar (because all corresponding angles are equal)
Since AB is 1/2 of AC, length of BE will be half of length of CD. To know the length of BE, you only need the length of CD.

Knowing only the angle BAE doesn't help because we do not have the length of any side available.
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for \$199

Veritas Prep Reviews

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13506
Followers: 577

Kudos [?]: 163 [0], given: 0

Re: If B is the midpoint of AC, what is the length of BE? [#permalink]

### Show Tags

23 Jul 2015, 06:03
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Senior Manager
Joined: 17 Jun 2015
Posts: 270
GMAT 1: 540 Q39 V26
GMAT 2: 680 Q46 V37
GMAT 3: Q V
Followers: 3

Kudos [?]: 20 [0], given: 165

Re: If B is the midpoint of AC, what is the length of BE? [#permalink]

### Show Tags

19 Dec 2015, 21:04
The two triangles are similar because of the AAA similarity.

Statement 1 only gives the ratio.

Statement 2: Gives a value and thus the side length too.

Hence B
_________________

Fais de ta vie un rêve et d'un rêve une réalité

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13506
Followers: 577

Kudos [?]: 163 [0], given: 0

Re: If B is the midpoint of AC, what is the length of BE? [#permalink]

### Show Tags

05 Jan 2017, 16:39
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: If B is the midpoint of AC, what is the length of BE?   [#permalink] 05 Jan 2017, 16:39
Similar topics Replies Last post
Similar
Topics:
3 In the triangle above, DE is parallel to AC. What is the length of DE? 4 10 Jun 2015, 03:12
If a/b=c, what is the value of ac? 1 15 Oct 2012, 09:00
13 If B is the midpoint of AC, what is the length of BE? 8 05 Feb 2012, 18:09
4 In triangle ABC, point X is the midpoint of side AC and 5 19 Jan 2010, 21:04
244 In triangle ABC, point X is the midpoint of side AC and 30 18 Aug 2009, 17:44
Display posts from previous: Sort by

# If B is the midpoint of AC, what is the length of BE?

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.