BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
Live EA class + 6 months of EA OnDemand
  • Expert-led weekly online sessions
  • EA Masterclass access between classes
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

130-point score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Surface area of the balloon

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 90
Joined: Mon Mar 02, 2009 6:06 am
Thanked: 3 times
by Baldini » Tue Apr 28, 2009 3:40 am
The volume of a sphere with radius r is (4/3)πr^3 and the surface area is 4πr^3. If a spherical balloon has a volume of 972π cubic centimeters, what is the surface area of the balloon in square centimeters?

(A) 324
(B) 729
(C) 243π
(D) 324π
(E) 729π

(π = pi)
OA is D.

Can someone please explain how to get to the answer?
thanks
GMAX
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 139
Joined: Wed Oct 22, 2008 4:36 am
Thanked: 17 times

by sacx » Tue Apr 28, 2009 4:49 am
I think surface area should be 4πr^2

We can find the radius of the balloon

(4/3)πr^3 = 972π
r^3 = 972 * 3/4
r = 9

Surface area = 4πr^2 = 4*π*9^2 = 324π
SACX
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 519
Joined: Sat Jan 27, 2007 7:56 am
Location: India
Thanked: 31 times

by Neo2000 » Tue Apr 28, 2009 4:50 am
Surface area of a sphere is 4(pi)r^2

You've got volume of a sphere. From that you can find r.

Once you have r, you can find th surface area.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 90
Joined: Mon Mar 02, 2009 6:06 am
Thanked: 3 times

by Baldini » Tue Apr 28, 2009 5:09 am
Thank you very much for your responses - but just to be sure, I have attached a screenshot of the original question (and will assume it was a typing error).
Attachments
mistype.doc
(179.5 KiB) Downloaded 178 times
GMAX
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1