What is the circumfrance of a circle that has a diameter of 18 cm?(pi=3.14)
A 21.14 cm2
B 56.52 cm
C 254.34 cm2
D 28.27 cm
Please show me how to do it!Thanks!^_^
2007-07-20 06:54:39 · 12 answers · asked by duh4296 1 in Science & Mathematics ➔ Mathematics
C = 2pi r or C = d pi
r = radius
d = diameter
C = 18pi
C = 56.52
B
2007-07-20 06:57:18 · answer #1 · answered by 7 · 1⤊ 0⤋
Well, then the radius is 18/2 = 9 cm, and use the formula 2(pi)r.
2007-07-20 13:58:10 · answer #2 · answered by Saif 2 · 1⤊ 0⤋
Formula: piD
Answer: B (3.14 X 18 = 56.52 )
2007-07-20 23:09:44 · answer #3 · answered by JDL Wahaha 3 · 0⤊ 0⤋
C = 2 * pi * r
r = d / 2
So in this case,
r = 18/2 = 9cm
C = 2 * pi * 9
= 18 pi
= 56.55 cm
B is the closest
2007-07-20 13:57:25 · answer #4 · answered by whitesox09 7 · 1⤊ 0⤋
the circumference is pi times diameter
= 3.14159 x 18 = 56.55 cm
2007-07-24 10:03:45 · answer #5 · answered by vlee1225 6 · 0⤊ 0⤋
circum of a circle=2.Pi.r
so,we have =2.(3.14).9
=56.52 cm i.e.,B ans
2007-07-20 14:10:02 · answer #6 · answered by MAHAANIM07 4 · 0⤊ 0⤋
C = Ï d
C = Ï x 18 cm
C = 56.52 cm
ANSWER B
2007-07-20 15:35:31 · answer #7 · answered by Como 7 · 0⤊ 0⤋
ok so first:
2piR = circumfrance
piR^2 = area
so plug the numbers in and you get:
2 x 3.14 x 9
which you can simply multiply out to get the answer.
2007-07-20 14:00:25 · answer #8 · answered by bluesclues 2 · 1⤊ 0⤋
Multiply pi by diameter of circle
3.14 * 18cm
answer b
2007-07-20 13:58:29 · answer #9 · answered by callmemiko 1 · 0⤊ 1⤋
R x Pie
half the diameter times by pie will give you the circumference
ps D
dudes circumference is radius not diameter!!
2007-07-20 13:58:23 · answer #10 · answered by first_gholam 4 · 0⤊ 1⤋