Last visit was: 21 Nov 2024, 19:08 It is currently 21 Nov 2024, 19:08

Close

GRE Prep 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
Your Progress

every week, we’ll send you an estimated GRE score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12196 [7]
Given Kudos: 136
Send PM
avatar
Supreme Moderator
Joined: 01 Nov 2017
Posts: 371
Own Kudos [?]: 470 [2]
Given Kudos: 0
Send PM
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12196 [0]
Given Kudos: 136
Send PM
avatar
Director
Director
Joined: 09 Nov 2018
Posts: 505
Own Kudos [?]: 133 [0]
Given Kudos: 0
Send PM
Re: In the above diagram, what is the value of x? [#permalink]
Didn't think in that way and taking time.
Manager
Manager
Joined: 05 Aug 2020
Posts: 101
Own Kudos [?]: 244 [1]
Given Kudos: 14
Send PM
Re: In the above diagram, what is the value of x? [#permalink]
1
Bookmarks
GreenlightTestPrep wrote:
GreenlightTestPrep wrote:

In the above diagram, what is the value of x?

NOTE: Enter your answer as a fraction

Show: ::
36/7


I added some letters to help guide the solution.



Area of triangle = (1/2)(base)(height)
IMPORTANT CONCEPT: we can use ANY of the three sides as our base.

So, for example, if we want to find the area of triangle ABC, we can use side AB as the base, or we can use side AC as the base, or we can use side BC as the base.

If we use side AB as the base, then the base has length 12 and the height is 3
So, area of triangle ABC = (1/2)(12)(3)

If we use side AC as the base, then the base has length 7 and the height is x
So, area of triangle ABC = (1/2)(7)(x)

IMPORTANT: If we use side AB as the base, the area of the triangle will be the same as the area we get if we use side AC as the base.

So, (1/2)(12)(3) = (1/2)(7)(x) [solve for x]
Divide both sides by 1/2 to get: (12)(3) = (7)(x)
Divide both sides by 7 to get: 36/7 = x

Answer: 36/7

Cheers,
Brent


Hey Brent.

I used properties of similar triangles to solve this question, and was wondering if that method is correct given your explanation using the area instead.

Using your labelled diagram, proving that triangle ADC is similar to triangle AEB went like this:

\(=>\) Triangle AEB has a right angle, and so does Triangle ADC
\(=>\) Triangle AEB and Triangle ADC share angle EAB
\(=>\) Since two of their angles are the same, their third angle must also be the same
\(=>\) Therefore, they are similar triangles

So it follows that:

\(\frac{7}{3} = \frac{12}{x}\)

\(7x = 36\)

\(x = \frac{36}{7}\)
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5030
Own Kudos [?]: 74 [0]
Given Kudos: 0
Send PM
Re: In the above diagram, what is the value of x? [#permalink]
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep 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.
Prep Club for GRE Bot
Re: In the above diagram, what is the value of x? [#permalink]
Moderators:
GRE Instructor
84 posts
GRE Forum Moderator
37 posts
Moderator
1111 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne