Question

Find the lateral area of a cylinder with base area of 49 Π in2 and a height that is twice the radius of its base.

196 Π in2
686 Π2 in2
169 Π in2
196 Π2 in2

Answer 1

whats the area of a circle?

Answer 2

i mean the formula for it, do you know it?

Answer 3

Formula for the cylinder correct?

Answer 4

No, let's start with the base first which is a circle and then move to the more complex one which is the cylinder area, ok?

Circle Area = pi*r^2
here we have 49*pi, so
r^2 = 49, can you find r = ?
hint: use square root.

Answer 5

I have to do sqrt 49 right?

Answer 6

yes, what will that give you for r?

Answer 7

7

Answer 8

what does that mean for the height h of the cylinder?
h = ?

Answer 9

That h = 7

Answer 10

but the question says "height that is twice the radius of its base." did you read the question and understood what is required? this is the most important of solving the question - is to understand everything about it :)

Answer 11

When it means twice we're talking about 7 x 7

Answer 12

no dear twice means 7+7

Answer 13

or 2 times 7

Answer 14

you have $10 and I have twice what you have, how much do I have? 100 or 20?

Answer 15

20$

Answer 16

that's the meaning of twice

Answer 17

now you know r = 7 and h = 14
find the circumference of the circle (or the base) using the formula 2*pi*r , can you work it out please?

Answer 18

14 (pi)

Answer 19

well done
now the lateral area of a cylinder if you google it
http://www.thefreemathtutor.com/lateralareaofacylinder.html
is 2*pi*r*h, we know already what 2*pi*r is and we know h, so can you work it out please?

Answer 20

196 (pi)

Answer 21

196 (pi) in^2

Answer 22

excellent

Answer 23

How about finding the surface area?

Answer 24

that will be
\[2\pi*r ^{2} + 2\pi*rh\]

Answer 25

294 (pi)^2

Answer 26

medal for you

Answer 27

How do I give a medal?

Answer 28

press the best response button on the correct answer, u get to do it only once per question

Answer 29

I have several questions to ask.

Answer 30

Okay, thanks.

Answer 31

you'll have to post each separately and let everyone get a fair go to help :)

Answer 32

I always bump it.