Fibd the length of the strapping needed to secure the pipe in the corner of the room as shown. the distance from a to b is 5.657 feet.

Then x^2 + x^2 = (5.657)^2 
(the triangle is isosceles.) 

2x^2 = 32 
so 
x^2 = 16 
x=4 

which is the radius of the circle! 

If the strapping is 1/4 the circumference and c= 2 pi r 

then the strapping is 2( 3.1416) 4 /4 

or 6.2832 inches