circumference of circle is 21.54 what is the radius?

Answer 1

Circumference of a circle formula

c = 2πr

c/2π = r

21.54/2(3,141592654 = r

21.54/6.2831185307 = r

3.428197474 = r

r = 3.4 rounded to one decimal place

The answer is r = 3.4

The radius is 3.4

Answer 2

Man! Are u dreaming or what ? It's the simplest question you can ever see in Mathematics! C'MON!!!
Circumference of a circle = 2*Pi*r where, r is the radius.
There you go:
So,
21.54 = 2 * Pi* r
so, the radius = 21.54 / (2 * Pi), Now you can do it after this!!!

Answer 3

C=2*pi*r, where C is the circumference and r is the radius.

21.54=2*pi*r, so r=21.54/(2*pi)=3.4282.

Answer 4

The formula for circumference is C = 2(pi)r

If we rearrange this for radius, we get

r = C/(2(pi))

Since we know the circumference is 21.54, we can make a substitution.

r = 21.54 / (2(pi))

Now just use your calculator!

Answer 5

circumfrance of a circle = pi x diameter
ie 21.54 = pi x (2 x radius) { diameter is twice the radius)
ie 2 x radius = 21.54 / 3.14 { approximate value of pi}
therefore radius = 6.86 /2 = 3.43

Answer 6

Hi. Remember pi? 3.1415926535..... Divide the circumference by pi to get the diameter. The diameter is twice the radius so divide it by 2.

Answer 7

Divide your answer by pi, which is 3.14 or 22/7. Use whichever one you prefer. This will give you the diameter of the circle. Divide the answer by two.This will give you the the radius.

Answer 8

Answer:
C = pi*d where C is circumference and d is diameter
21.54 = 3.14*d
d=21.54/03.14
d = 6.85
r=6.85/2
r=3.42

Answer 9

The formula for the circumference is 2(PI)d
The formula for the radius is d/2

21.54 = 2(PI)d
21.54/2(PI) = d

d = 3.43

r = 3.43/2 = 1.71

Answer 10

rad = circ / pi / 2
rad = 21.54 / 3.14 / 2
21.54 / 3.14 / 2 =3.43
rad = 3.43