Question

calculate the length of the circumfrence of a circle with diameter of 3.3m

Answer 1

The formula to find the circumference of a circle is : 
$c=2 ~pi~ r$
To find the radius we would divide 3.3 by 2
The radius is always HALF of the diameter. 
3.3/2=1.65
Now we know r=1.65
So we plug that into the circumference formula:
$c=2(3.14)(1.65)$
pi=3.14
Once you multiply all the numbers together you get:
C=10.36m

Answer 2

C= d*π
⇒ C= (3.3 m)*π
⇒ C= 10.367 m

The circumference of the circle is 10.367 m~