A community for students.
Here's the question you clicked on:
 0 viewing
 3 years ago
Find the length of the diameter of a sphere with a surface area of 490.87 km2.
A. 12.5 km
B. 25 km
C. 6.25 km
D. 3.125 km
 3 years ago
Find the length of the diameter of a sphere with a surface area of 490.87 km2. A. 12.5 km B. 25 km C. 6.25 km D. 3.125 km

This Question is Closed

TuringTest
 3 years ago
Best ResponseYou've already chosen the best response.2\[A=4\pi r^2\]\[d=2r\]

meverett04
 3 years ago
Best ResponseYou've already chosen the best response.3Using @Turing's formulas we have A = 4(pi)d^2 Then substituting in the known values we have 490.87/pi = d^2 Taking the square root d = 12.50 The answer is A

zbay
 3 years ago
Best ResponseYou've already chosen the best response.0Did it again and i still have D

fewscrewsmissing
 3 years ago
Best ResponseYou've already chosen the best response.0Turing's formula's are right, and meverett's working correct. Here's another approach: \[\Large \begin{array}{l} A = 4\pi {r^2}\\ d = 2r\\ r = \frac{d}{2}\\ A = 4\pi {\left( {\frac{d}{2}} \right)^2}\\ {\left( {\frac{d}{2}} \right)^2} = \frac{A}{{4\pi }}\\ \frac{d}{2} = \sqrt {\frac{A}{{4\pi }}} \\ d = 2\sqrt {\frac{A}{{4\pi }}} \\ d = 2\sqrt {\frac{{{\rm{49}}0.{\rm{87}}}}{{4\pi }}} \\ = 12.499951\\ = 12.5 \end{array}\] Which is A.
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.