SOLUTION: A sphere has a surface area of 200 square centimeters. Which choice is the best approximation of its diameter? Use 3.14 to approximate pi.

Algebra ->  Surface-area -> SOLUTION: A sphere has a surface area of 200 square centimeters. Which choice is the best approximation of its diameter? Use 3.14 to approximate pi.      Log On


   

Question 855202: A sphere has a surface area of 200 square centimeters. Which choice is the best approximation of its diameter? Use 3.14 to approximate pi.
Found 2 solutions by mananth, Theo:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
The surface area of a sphere is given by
S+=+4+pi+r%5E2
200=+4+pi+r%5E2
200+=+4%2A3.14%2Ar%5E2

r%5E2=+200%2F%284%2A+3.14%29
r^2=15.92
r = +/- 3.99 = +/-4
So radius = 4

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
pi = 3.14
surface area = 200 square cm.
formula for surface area of a sphere is:
sa = 4*pi*r^2
replace variables with what you know to get:
200 = 4*3.16*r^2
simplify to get:
200 = 12.56*r^2
divide both sides of this equation by 12.56 to get
200/12.56 = r^2
simplify to get:
15.92356688 = r^2
take the square root of both sides of this equation to get:
3.990434422
since diameter is equal to 2 times the radius, you get:
d = 2*r = 7.980868845
your answer will be either:
8 or 8.0 or 7.98 or 7.981 or 7.9809
depending on how many decimal places the selection have been rounded to.