What is the radius....?

Question

haha i'm a little zonked right now and don't really remember how to do math....

If the circumferance is 40 then what is the radius?

I know its c=2(pie)r

but I dont know what r is.... lol

Yes i know i'm lazy but it would be a great help...

I think the radius is 6.36..... not too sure

because 2X(pie) is 6.28 and 6.28X6.36 is 39.91.... i think thats as close as i can get

Answer 1

C = 2(pi)(radius)

40 = 2(pi)(radius)

40 = 6.28(radius)

40 / 6.28 = radius

The radius is 6.3694267515923566878980891719745

Rounded up: 6.37 is the radius

Answer 2

6.3661977236758134307553505349006

Circumference = Pi*diameter

40 = 3.14*x

40/3.14 = 3.14/3.14

12.73

Radius = diameter/2

12.73/2 = 6.366...  

Answer 3

C = 2 (pie) r

C = 40

40 = 2 (pie) r

r = 40/[2 (pie)]

r = 40/6.23

r = 6.42

If you were rounding to a solid number, you'd probably round to 7.  

Answer 4

Radius is half of diameter

so radius = 40/2 which equals 20 then 20/(pie) which equals

6.366197724 units

Answer 5

Circumference of the circle is 40' correct?

And 'pi' is 3.1417, correct?

So, divide 3.1417 into 40 and what do you get as an answer? and half (1/2) of the diameter is the radius, yes?

So, would 40 divided by 3.1417 = _____ ?

And, since radius is HALF of the diameter, divide the above answer by 2 !!!

Easy-peasy, yes? YES !!!

Rule of "Rounding:" if the last number is 1,2,3 or 4, you round DOWN. If the last number is 5,6,7,8 or 9 you round UP.

Therefore, 6.357 becomes 6.36

(so, 6.353 would be 6.35; 6.359 would be 6.36; 6.36 would be 6.4;

and 6.25 would be 6.3, yes?)

Answer 6

r=c/2pi