surface area of a cylinder ?

Question

okay I have to find the surface of a cylinder thats diameter is 4 inches the radius is 2 inches and the height is 1.5 inches .. how do I do that ? oh yeah and my teacher wants me to make pi, 3 instead of 3.14 so it comes out evenly . so if you help me with this in your equation please make pi 3 ! thank you in advance if you help me with this .

oh yeah this was homework my math teacher gave me . I did it once . but I messed up and shes making me re do it but I don't quite understand how so thats why I'm posting this .

wait a second ... I got 18 for the volume so how can the surface area be 18 too ?

Answer 1

The surface area of a cylinder is as follows:

A = (area of the top and bottom) + (area of the sides)

Note that the top and the bottom are just circles, and we know the formula for circles (pi * r^2). The area of the side portion, however, is more like the circle's circumference (2pi(r)), but extended with a height. That's all there is to it.

A = 2*pi(r^2) + 2pi(r)h

Use this fact into your calculation.

Answer 2

Surface area = pi x d x h = 3 x 4 x 1.5 = 18 inch square

Volume = pi x r x r x h = 3 x 2 x 2 x 1.5 = 18 inch cube

Answer for both is 18 but units are different

Answer 3

To find the surface area of the cylinder you need to know the circumference of the cylinder

this is found by the formual Pi D

where pi = 3 (as you request)

so 3 x 4 (diameter) = 12 inches

to find the area multiply the circumference (12) by the height
so 12 x 1.5 = 18 sq inches

basically this is the same as finding the area of a square or rectangle .. Imagine the circumference rolled out flat so that it makes a square instead of a cylinder. The height is the other side so multiply one side by the other side gives you the area

Answer 4

Surface area of the top and bottom are each (pi)*r^2 = 3*2^2 = 12.
Surface area of the side is (pi)*d*h = 3*4*1.5 = 18.
==> total surface area = top + bottom + side = 12 + 12 + 18 = 42.

Answer 5

The lateral surface area is 2(pi)(radius)(height of cylinder).

If you are also to include the area of the top and bottom, each would be the area of a circle (pi)(radius)^2.

So the total surface area would be: 2(pi)(radius)(height) + 2(pi)(radius)^2. You can handle the arithmetic.

Answer 6

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 ¶r2. There are two ends so their combinded surface area is 2*¶r2. The surface area of the side is the circumference times the height or 2¶rh.
The entire formula for the surface area of a cylinder is 2*¶r2 + 2¶rh.

Answer 7

the surface of the circles
=(2)(pi)(radius^2)
=(2)(3)(2^2)
=24 inches^2

the surface of the rectangle
=(2)(pi)(radius)(height)
=(2)(3)(2)(1.5)
=18 inches^2

the surface of the cylinder
=circle+rectangle
=24+18
=42 inches^2

Answer 8

SA = 2*pi*r*h + 2*pi*r^2
= 6pi + 8pi
= 14pi

Answer 9

im no longer gonna provide the respond : P you are able to desire to learn ! heres help nevertheless :) to locate the floor are of the full cylinder you are able to desire to characteristic the floor component of the two circles and the floor component of the different (rectangular-ish) shape. circle floor section = pi (3.14) situations the radius (2.5) situations the radius (2.5) multiply that answer by potential of two so as which you get the component of the best AND backside circles different floor section = circle circumfrence [diameter (radius situations 2 .. 18.6 + 18.6) situations pi (3.14) upload that quantity to component of the circles and theres your answer !! desire that helped !! :)