Question 334899
1. The area of a circle is 28 sq meters. What is the circumference?
Find r from the area:
{{{pi*r^2}}} = 28
r = {{{sqrt(28/pi)}}}
;
Find the circumference
C = {{{2*pi*r}}}
Replace r with{{{sqrt(28/pi)}}}
C = {{{2*pi*sqrt(28/pi)}}}
enter into a calc
C = 18.758 m
:
:
2. A cylinder drum has a diameter of 3 yards and a volume of 65 cubic yards.
 What is height of drum
Vol of a cylinder
{{{pi*r^2*h}}} = V
Find the radius: r = 3/2 = 1.5 yds
{{{pi*1.5^2*h}}} = 65
{{{pi*2.25*h}}} = 65
h = {{{65/(2.25*pi)}}}
using a calc
h = 9.1956 yds is the height
:
;
Check by finding the vol with this height
V = {{{pi*1.5^2*9.1956}}} 
V = 65.00