Cylinders!!! Volume, and Surface Area?

Question

What are the Surface Area and Volume of these two cylinders?

1) Radius=7cm
Height=10cm
Surface Area=?
Volume=?

2) Diameter=10cm
Height=25cm
Surface Area=?
Volume=?


Help!!!

Answer 1

For cylinder,
volume, v = pi x r x r x h
surface area, s =( 2 x pi x r x h ) + 2(pi x r x r)

where r = radius, h = height
the last term for surface area 2(pi x r x r) are for the top and bottom covers if there is.


1) Radius=7cm
Height=10cm
Surface Area =( 2 x pi x r x h ) + 2(pi x r x r)
= (2 x pi x 7 x 10) + 2(pi x 7 x 7)
= 140pi + 98pi
= 238pi
= 747.7 cm^2

Volume=pi x r x r x h
= pi x 7 x 7 10
= 490pi
= 1539.38 cm^3

2) Diameter=10cm
Height=25cm
Hence, radius = 10/2 = 5cm
Surface Area =( 2 x pi x r x h ) + 2(pi x r x r)
= (2 x pi x 5 x 25) + 2(pi x 5 x 5)
= 250pi + 50pi
= 300pi
= 942.5 cm^2

Volume=pi x r x r x h
= pi x 5 x 5 x 25
= 1963 cm^3

Answer 2

First of the formula findind the surface area of a cylinder is 2 area of the circles + the circumference( height). then the formula of the volume is pi r^2(height)

1)SURFACE AREA
2(pi 7^2) + 2pi(7) times 10
98pi+ 140pi=238pi
S= 238picm^2

VOLUME

pi7^2 times 10=490pi
V=490picm^3

2)SUFACE AREA

2(pi5^2) + 2pi(5) times 25
50pi+250pi=300pi
S=300picm^2

Volume

pi5^2 times 25=625pi
V=625picm^3

Answer 3

The volume of a cylinder is H * pi * r^2.

The surface area of the tube is 2 * pi * r * h (height * circumference).

If they want you to include the top and bottom, add in 2 * pi * r^2

Answer 4

Volume = π • r² • height = ¼ • π • d² • height

v = 3.14 * (7^2) * 10 = 1538.6


(1 / 4) * 3.14 * (10^2) * 25 = 1962.5

Answer 5

I think

1
surface area=(22/7)*(1/2)*20+(22/7)*14
Volume=(1/3)*((22/7)*7*7)*10

use the same think on the other one