Find the area and the circumference of a circle with diameter 4cm
Use the value for 3.14 π, and do not round your responses. Be sure to include the correct units in your responses.
Area:
Circumference:
I really need help with pi?
2008-08-27 5:37 pm
回答 (5)
2008-08-27 5:45 pm
✔ 最佳答案
You simply need to memorize the following formulae...A = π * Radius * Radius or πR^2
C = π * Diameter or πD
Remember that the Radius = 1/2 the diameter
Now, just multiply...
A = 3.14 * (2cm)^2 = 3.14 * 4cm^2 = 12.56 cm^2
C = 3.14 * 4cm = 12.56 cm
Note that the answers seem to be the same, but one is in Square centimeters, and the other in centimeters. Area and Length are different.
2008-08-28 12:48 am
1)
a = Ïr^2
(area = pi * radius * radius)
Ï(4/2)^2
= 3.14(2)^2
= 3.14(4)
= 12.56 cm²
= = = = = = = =
2)
c = Ïd
(circumference = pi * diameter)
4Ï
= 4(3.14)
= 12.56 cm
a = Ïr^2
(area = pi * radius * radius)
Ï(4/2)^2
= 3.14(2)^2
= 3.14(4)
= 12.56 cm²
= = = = = = = =
2)
c = Ïd
(circumference = pi * diameter)
4Ï
= 4(3.14)
= 12.56 cm
2008-08-28 12:49 am
C = pi*d
C = pi*4
C = 4pi cm
A = pi*(d^2)/4
A = pi*(4^2)/4
A = 16pi/4
A = 4pi cm^2
C = pi*4
C = 4pi cm
A = pi*(d^2)/4
A = pi*(4^2)/4
A = 16pi/4
A = 4pi cm^2
2008-08-28 12:45 am
Area = pi r^2
circumference = 2 pi r
where
r= radius = d/2
d= diameter
pi approx = 3.14 (by your assignment)
Area = (3.14)(2)^2 = (3.14)(4) cm^2
you can multiply this out.
circumference = (2)(3.14)(2) = (3.14)(4) cm
You do the rest. (If you have been discussing
the topic of "significant figures" then you might be only able
to save the result to the nearest ones place)
circumference = 2 pi r
where
r= radius = d/2
d= diameter
pi approx = 3.14 (by your assignment)
Area = (3.14)(2)^2 = (3.14)(4) cm^2
you can multiply this out.
circumference = (2)(3.14)(2) = (3.14)(4) cm
You do the rest. (If you have been discussing
the topic of "significant figures" then you might be only able
to save the result to the nearest ones place)
2008-08-28 12:44 am
The equation is:
C = dÏ
You're given the diameter and the value of Ï to use, so just plug them in and solve:
C = 4 * 3.14
C = 12.56 cm
C = dÏ
You're given the diameter and the value of Ï to use, so just plug them in and solve:
C = 4 * 3.14
C = 12.56 cm
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