tell how u got it
2007-10-25 06:15:30 · 6 answers · asked by cory j 1 in Science & Mathematics ➔ Mathematics
the diameter is 18. the radius is 9. area is pi r squared. the answer is 81 pi centimeters
2007-10-25 06:18:59 · answer #1 · answered by swim queen 2 · 0⤊ 0⤋
C/D = pi
18pi/D = pi
18pi = pi 2 R
(18pi)/(2pi) = R = 9.
Area within the circle = pi RR = p 99 cm cm
2007-10-25 06:51:51 · answer #2 · answered by Mark 6 · 0⤊ 0⤋
the area of a circle is done by this formula
A= Ï r^2 Area = (pi){radius x radius}
radius is = 1/2 circumference (half of the circumference
radius = 1/2 x 18 Ï = 9 Ï
Area = Ï (9 Ï x 9 Ï) = 81 Ï^3
2007-10-25 06:29:51 · answer #3 · answered by robrdz1983 1 · 0⤊ 0⤋
we have circumferance= 2pi*r=18pi
this gives r=9
ares of the circle=pi*r^2
therefore required area =pi(9)^2=81pi cm^2.
2007-10-25 06:38:48 · answer #4 · answered by rk 2 · 0⤊ 0⤋
C = 2pir = 18pi
So r = 18 pi/2pi = 9
A = pir^2= 81pi cm^2
2007-10-25 06:20:20 · answer #5 · answered by ironduke8159 7 · 2⤊ 0⤋
circumference = 2Ïr = 18Ï
ie raduis = 9 cm
so area = Ïr^2
= 81Ï
that's all
best of luck ; )
2007-10-25 06:53:12 · answer #6 · answered by crazy_haboush 2 · 0⤊ 0⤋