Question 204772
A piece of wire 30com long is cut into two pieces. 
One of these is bent into a circle and the other is bent into a square enclosing the circle. 
What is the diameter of the circle?
;
The diameter of the circle is also the side of the square
:
Let x = the diameter and the side of the square
;
Circum + perimeter = 30
pi*x + 4x = 30
;
4.71416x = 30
x = {{{30/4.71416}}}
x = 4.2 cm is the diameter of the circle
:
:
Check
circum: 4.2*pi = 13.195
perime: 4 * 4.2= 16.80
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wire length  = 29.995 ~ 30