1. Height=10cm Radius=6.5cm
2. Height=6.5cm Radius=10cm
2007-04-09 11:17:45 · 15 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
the cylindrical surface is 2pi rh
the ends are each pi r^2
so total is 2pi r(r+h)
2007-04-09 11:23:49 · answer #1 · answered by hustolemyname 6 · 1⤊ 0⤋
Find the lateral surface area by multiplying the circumference x height. The add the surface of the two circles: 2 x pi x radius^2.
1. 13 x pi ( diameter x pi =circumference) x 10 + 2 x pi x 6.5^2
2007-04-09 11:27:39 · answer #2 · answered by Thomas M 2 · 0⤊ 0⤋
A closed cylinder has three parts: one end, the other end, and the cylinder itself. The two ends are identical and have an area of pi*r^2. The cylinder has an area of 2*pi*r*h.
For your first problem:
Solve for one end:
pi*r^2 = pi*42.25 or about 132.73
Solve for the cylinder:
2*pi*r*h = 2*pi*6.5*10 = 130*pi or about 408.4
Two ends plus the cylinder =
2*132.73 + 408.4 = 673.86 cm^2
or more precisely 42.25pi + 42.25pi + 130pi = 214.5pi
Do the second one the same way, but switch the 10 and the 6.5
2007-04-09 11:30:02 · answer #3 · answered by dogsafire 7 · 0⤊ 0⤋
Surface area of cylinder: top + bottom + sides
top and bottom are circles Area circle = pi r^2, we have two
then add side which is 2(pi)(radius) (height)
Surface Area = 2 pi r^2 + 2 pi r h
I'll let you plug the values in
:)
2007-04-09 11:23:25 · answer #4 · answered by Anonymous · 1⤊ 0⤋
To find the surface area of a cylinder add the surface area of each end plus the surface area of the side. The surface area of each end is the p r2. There are two ends so their combinded surface area is 2 p r2. The surface area of the side is the circumference times the height or 2 p r h
The entire formula for the surface area of a cylinder is 2 Ï r2 + 2 Ï r h
2007-04-09 11:22:32 · answer #5 · answered by rt1290 6 · 1⤊ 0⤋
Area of ends is Pi R squared = 3.1412 x 6.5 x 6.5 = 132.716 x 2 for 1. and 3.1416 x 10 x 10 = 314.12 x 2 for 2.
The area of the cylinder walls is Circumference x height - circumference = 2 Pi R (or Pi D). 1. is 40.8408 x10 and 2. is 62.8320 x 6.5
Therefore cylinder 1. is 673.84 sq. cm's and cylinder 2. is 1036.648 sq. cm's.
2007-04-09 11:45:52 · answer #6 · answered by Gordon B 4 · 0⤊ 0⤋
Imagine unfolding the cylinder. As you unfold it you will have three pieces. A square, (as you unfold the middle part we realize it's nothing but a square), and 2 circles.
You just need to find the height of each of these.
Area Of Circle: A=pi*r^2
Area Of Square: A = L * H
The tricky part is realizing that the L part of the area of a square is the circumference of the circle which we know to be: 2*pi*r
This leaves us with (square): A = (2 * pi * r) * H
2007-04-09 11:23:29 · answer #7 · answered by snard6 2 · 1⤊ 0⤋
The area of the top and the bottom of the cylnder is pi*r^2 - the formula of the lateral area is 2*pi*r*height Add those two results together(remember you have to use two times the top and bottom) to come up with the right answer.
2007-04-09 11:21:28 · answer #8 · answered by Paul 2 · 1⤊ 0⤋
surface area = height times circumference plus twice radius squared, all times pi
1. SA = 214.5 pi
2. SA = 330 pi
2007-04-09 11:24:52 · answer #9 · answered by badaerozepstones 3 · 1⤊ 0⤋
Use the formula 2ÃÏÃrÃ(h + r), where r is the radius of the circular base, and h is the height.
So...
1. 2 x Ï x 6.5 x (10 + 6.5)= about 674cm
2. 2 x Ï x 10 x (6.5 + 10)= about 1036cm
Hope that helped :)
2007-04-09 11:25:26 · answer #10 · answered by Anonymous · 0⤊ 0⤋
Surface Area = Area of the Circles on sides + Area between circles (take it and make it into a rectangle to make it easier to calculate)
SA= 2(pie*r^2) + length*width
SA= 2pie*r^2 + Height*Circumference
SA= 2pie*r^2 + h*2r*pie
SA= 2r*pie(r+h)
1. 2(6.5)(3.14)(16.5)
673.53 cm^2
2. 2*10*3.14*16.5
1036.2 cm^2
2007-04-09 11:25:58 · answer #11 · answered by the man 2 · 0⤊ 0⤋