Question 286443
Circle has an area of 25 cm2,
 what is its circumference to the nearest tenth of a centimeter? 
:
Find r:
{{{pi*r^2}}} = 25
{{{r^2}}} = {{{25/pi}}}
r = {{{sqrt(25/pi)}}}
Use a calc
r = 2.821
:
Find the circumference
c = {{{2*pi*2.821}}}
c = 17.72 cm
:
:
Determine volume of a sphere to nearest cm if surface area is 113 cm2: 
Find r using the Surface area formula:
{{{4*pi*r^2}}} = 113
{{{r^2}}} = {{{113/(4pi)}}}
Using a calc
r = {{{sqrt(113/(4pi))}}}
r = 2.9987 ~ 3
:
Find volume
v = {{{(4/3)pi*r^3}}}
v = {{{(4/3)pi*3^3}}}
v = {{{(4/3)pi*27}}}
using a calc
v = 113.1 cu/cm