It is currently 30 Nov 2020, 18:52

### 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

# In the figure above, arcs PR and QS are semicircles with ce

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Founder
Joined: 18 Apr 2015
Posts: 13927
GRE 1: Q160 V160
Followers: 315

Kudos [?]: 3687 [0], given: 12945

In the figure above, arcs PR and QS are semicircles with ce [#permalink]  18 Jun 2019, 21:58
Expert's post
00:00

Question Stats:

95% (00:45) correct 4% (02:01) wrong based on 47 sessions
Attachment:

#GREpracticequestion In the figure above, arcs PR and QS .jpg [ 49.47 KiB | Viewed 1424 times ]

In the figure above, arcs PR and QS are semicircles with centers at Q and R respectively. If PQ = 5, what" is the perimeter of the shaded region?

(A) $$5\pi + 5$$

(B) $$5\pi + 15$$

(C) $$10\pi + 10$$

(D) $$10\pi + 15$$

(E) $$100\pi$$
[Reveal] Spoiler: OA

_________________

New to the GRE, and GRE CLUB Forum?
GRE: All you do need to know about the GRE Test | GRE Prep Club for the GRE Exam - The Complete FAQ
Search GRE Specific Questions | Download Vault
Posting Rules: QUANTITATIVE | VERBAL
FREE Resources: GRE Prep Club Official LinkTree Page | Free GRE Materials - Where to get it!! (2020)
Free GRE Prep Club Tests: Got 20 Kudos? You can get Free GRE Prep Club Tests
GRE Prep Club on : Facebook | Instagram

Questions' Banks and Collection:
ETS: ETS Free PowerPrep 1 & 2 All 320 Questions Explanation. | ETS All Official Guides
3rd Party Resource's: All Quant Questions Collection | All Verbal Questions Collection
Books: All GRE Best Books
Scores: The GRE average score at Top 25 Business Schools 2020 Ed. | How to study for GRE retake and score HIGHER - (2020)
How is the GRE Score Calculated -The Definitive Guide (2021)
Tests: GRE Prep Club Tests | FREE GRE Practice Tests [Collection] - New Edition (2021)
Vocab: GRE Prep Club Official Vocabulary Lists for the GRE (2021)

GRE Prep Club Tests Editor
Affiliations: Partner at MyGuru LLC.
Joined: 13 May 2019
Posts: 152
Location: United States
GMAT 1: 770 Q51 V44
GRE 1: Q169 V168
WE: Education (Education)
Followers: 8

Kudos [?]: 163 [5] , given: 3

Re: In the figure above, arcs PR and QS are semicircles with ce [#permalink]  19 Jun 2019, 09:35
5
KUDOS
Expert's post
Quote:
In the figure above, arcs PR and QS are semicircles with centers at Q and R respectively. If PQ = 5, what" is the perimeter of the shaded region?

In GRE geometry questions, always look for logical estimation opportunities and solve for the easy shape or value first.

In this case we can see that drawn shaded interior radius PQ = undrawn radius QR = drawn shaded radius RS, and each of those radii length = 5.

Then, we can solve of the straight portion of the figure which is PQ + RS = 10.

Look to the answer choices to see which include the value of 10 since the circle must include π.

Only Choice C includes the necessary value of 10, so select Choice C without even needing to spend the time calculating the included circumference which would have been 2πr = 2π x 5 = 10π.
_________________

Stefan Maisnier

Sign up today for a free 30-minute online GRE tutoring session!

Intern
Joined: 12 Nov 2020
Posts: 2
Followers: 0

Kudos [?]: 1 [0], given: 18

Re: In the figure above, arcs PR and QS are semicircles with ce [#permalink]  21 Nov 2020, 06:07
I am unclear about the math, if anybody can give an explanation about it.
GRE Prep Club Tests Editor
Affiliations: Partner at MyGuru LLC.
Joined: 13 May 2019
Posts: 152
Location: United States
GMAT 1: 770 Q51 V44
GRE 1: Q169 V168
WE: Education (Education)
Followers: 8

Kudos [?]: 163 [1] , given: 3

Re: In the figure above, arcs PR and QS are semicircles with ce [#permalink]  22 Nov 2020, 09:07
1
KUDOS
Expert's post
Kafi22 wrote:
I am unclear about the math, if anybody can give an explanation about it.

The formula for perimeter of a semicircle = diameter + πr.

Since the radius for either semicircle is 5, then the the perimeter of a single semicircle = 10 + 5π.

However, there are two semicircle arcs included in the shaded figure, so the shaded perimeter = 10 + 5π + 5π = 10 + 10π, choice C.

Of course, I stand by the earlier estimation as possibly a more efficient path to solving on the actual GRE.
_________________

Stefan Maisnier

Sign up today for a free 30-minute online GRE tutoring session!

Re: In the figure above, arcs PR and QS are semicircles with ce   [#permalink] 22 Nov 2020, 09:07
Display posts from previous: Sort by

# In the figure above, arcs PR and QS are semicircles with ce

 Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.