Well, there's a drawing of a cylinder and neither the radius (nor diameter) or height are given. All it says is:
a. The base of this cylinder has an area of 302.5 pi cm squared. Find the cylinder's radius.
b. The rectangular piece that can be used to form the curved side of this cylinder has an area of 110 pi cm squared. Find the cylinder's height.
I got 9.8 cm for the radius, is that what you came up with??? If not, can you please show me your steps.
I can't seem to figure out what the height is...Can you please help me and explain how you got it, or at least show the steps?
PLEASE and THANKS, I really appreciate any help with this!!!
2007-03-26 10:10:42 · 4 answers · asked by Dee 6 in Education & Reference ➔ Homework Help
a) Area of Base = pi * r^2 = 302.5 * pi
r^2 = 302.5 r = sqrt(302.5) = 17.3
You took 1/2 of the radius thinking you were calculating the diamter.
b) Circumfrence of Base is C = pi * d = pi * 2 * r
C = pi * d = pi * 34.6
Area of rectangular piece is 110 * pi
One edge of the rectangular area is the circumference of the base.
110 * pi = pi * 34.6 * h where h is height of cylinder equals height of rectangular area.
h = 110/34.6 = 3.179 cm
2007-03-26 10:25:44 · answer #1 · answered by KingGeorge 5 · 1⤊ 0⤋
(a) You are not given the radius because in (a) that is what you are being asked to find.
The area of the base in cm squared is pi * r^2, and this is equal to
302.5 * pi.
302.5 * pi can be written pi * 302.5.
So what is r^2?
When you have seen that, take the square root to get r.
(It is not 9.8 cm. Key 302.5 in your calculator and press the square root sign.)
(b) Now you have r, you can work out the area of the curved surface. That is
2 * pi * r * h.
So 2 * pi * r * h = 110 * pi
Divide both sides of this equation by 2 * pi * r
You get h = 55 / r
You have r from part (a) of the question.
Key in 55 [ divide sign ] r, and you have the answer in cm.
2007-03-26 17:27:58 · answer #2 · answered by Anonymous · 1⤊ 0⤋
The base is a circle; The area is pi*r^2. So the radius is the square root of 302.5 . After you figure out the radius you can figure out the circumference and then you will know the height. I think you will find it is close to 20.
2007-03-26 17:23:21 · answer #3 · answered by Nelson_DeVon 7 · 1⤊ 0⤋
Yes!!!!!!!
2007-03-26 17:17:50 · answer #4 · answered by francesca p 1 · 0⤊ 2⤋