Find the diameter, to the nearest mm, of a sphere with surface area 215.8cm squared.

Question

anonymous · Answer

$$surface\:\:\:\:area =4* \pi*r^2$$ 
$$ 215.8 = 4*\pi*r^2$$
$$2r =d$$
r is radius and d is diameter

anonymous · Answer

i feel it is 4.143176208 cm

anonymous · Answer

I have the answer with me but it is not the one above.
I am confused on how to solve this problem.

anonymous · Answer

what is the formula of sphere surface area?

anonymous · Answer

SA=4piersquared

anonymous · Answer

thus, 215.8 =4*(22/7)*r^2
r^2 = 215.8/(4*3.14)
r = (17.16590909)^(1/2)
r =4.143176208 cm 
this is ur answer now u can cross check it!!!!!!!!!!!

anonymous · Answer

The answer in the back of book says the diameter is 83mm

anonymous · Answer

ok buddies now feeling lil bit tired now goin to have a cup tea.................

anonymous · Answer

will be back soon............

anonymous · Answer

enjoy your tea!

anonymous · Answer

I did it again it's alright maybe some misprint in your book

anonymous · Answer

Okay, I guess so. Thanks for the help though.

anonymous · Answer

No Problem

anonymous · Answer

hey ur answer is correct diameter = 2 * radius
Diameter = 2* 4.143176208 =8.286352416cm aprox. 83 mm

anonymous · Answer

Thanks Sheg!

anonymous · Answer

This posting corrects an earlier posting which I deleted.  To convert cm^2 to mm^2 the decimal point has to be shifted two places to the right (multiplyied by 100).  Solve the following for d:$$21580=4 \pi  \left(\frac{d}{2}\right)^2$$d = 82.8802 or 83 mm^ rounded to the nearest mm.