Question

Help Needed!

Answer 1

this site is about to go down until the mods unban bibby permanently

Answer 2

\[V = \pi r ^2 h\]

Answer 3

So V = 3.14 * 1.9^2 * 11 ?

Answer 4

Looks good

Answer 5

So the answer is 124.6894

Answer 6

124.75

Answer 7

m^3

Answer 8

Well I have answer choices...

a. 75.449 pi m^3
b. 49.02 pi m^3
c. 41.8 pi m^3
d. 39.71 pi m^3

Answer 9

I don't think thats correct...

Answer 10

Oh in terms of pi

Answer 11

So don't include pi in your calculation, leave it alone.

Answer 12

Okay so is 65.626...

Answer 13

No, how did you get that?

Answer 14

I did 3.14 * 1.9 * 11 ?

Answer 15

You should have ...pi m^3

Answer 16

No leave pi alone, look at your choiced

Answer 17

choices, just do 1.9^2*11

Answer 18

When it says leave it in terms of pi, it means your answer should look as such \[(some~~ number) \pi~ m^3\]

Answer 19

39.71 ....

Answer 20

Yes :)

Answer 21

Can you help me with 2 more?

Answer 22

Well I'm about to sleep, but if it's short sure.

Answer 23

So I just 3^2 * 6

Answer 24

What are the dimensions? :P

Answer 25

Opps
h = 6 in
r = 3 in

Answer 26

Same formula

Answer 27

3^2 * 6?

Answer 28

Looks good

Answer 29

The answer is 54

Answer 30

??

Answer 31

Yes, if the cylinders height is given, that looks good.

Answer 32

@dumbcow @zepdrix Can you help me with the problem above? ^^

Answer 33

Split them up. 3cm * 8cm * 5cm and then add that to 6cm * 2cm * 5cm

Answer 34

use volume of rectangle prism ----> v = l*w*h

the figure has 2 rectangle prisms so find both volumes, then add them together

Answer 35

agreed @dumbcow

Answer 36

So

3cm * 8cm * 5cm = 120

6cm * 2cm * 5cm = 60

Answer 37

Which is 180...

Answer 38

Correct?

Answer 39

yes

Answer 40

Okay, I have one last question.

The lateral area of a cone is 555 pi cm^2. The radius is 15 cm. What is the slant height to the nearest tenth of a centimeter?

Answer 41

i got no idea about it ...sorry =(
this might help https://www.google.com/search?newwindow=1&es_sm=122&q=area+of+a+cone&oq=area+of+a+cone&gs_l=serp.3..0l10.96720.100181.0.100261.20.13.1.0.0.1.325.1745.0j2j3j2.7.0.msedr...0...1c.1.64.serp..13.7.1559.LuGH0APJuZs

Answer 42

AreaCone = pi*r*slant

Answer 43

How do I find the slant?

Answer 44

Lateral area is the area on the outside on the slant, not the bottom.



Formula is PI times Radius times the square root of the height squared plus the radius squared, for the lateral height.

555 pi = 15 pi * square root of h^2 + square root of 15^2

555 pi = 15pi * square root (h^2 + 225)
Divide both sides by 15pi
37 = square root (h^2 + 255)
Square both sides
1369 = h^2 + 255
h^2 = 1144
Take square root
h = 2 square root 286

But that's height, not lateral height. It's a right triangle

a^2 + b^2 = c^2
2 square root 286 squared + 15 squared = c^2

c = square root of 797

That's the lateral height.

Answer 45

So whats the slant? How do I find the? Im confused..

Answer 46

= 28.23cm~

Answer 47

Slant would be c. You have to find a first

Answer 48

How do I find a?

Answer 49

All explained above in my long reply. The "h" here is the "a"

555 pi = 15pi * square root (h^2 + 225)
Divide both sides by 15pi
37 = square root (h^2 + 255)
Square both sides
1369 = h^2 + 255
h^2 = 1144
Take square root
h = 2 square root 286

Answer 50

So whats the formula I do to find the answer.

Answer 51

It's not just one formula.
First the formula of a lateral area of a cone, plug in what you have which is everything except h. Then you put h into the pythagorean theorem and h is the height of the cylinder or "a" in my equation and then "b" is the radius and "c" is what you're solving for.

Answer 52

That was weird, my OS went down, but it seems you have more than enough help :), also next time please try to keep one question per post, thanks!

Answer 53

Sorry my OS keeps shutting down too...

Answer 54

The answer is 21.7, correct?

Answer 55

Not from my math. If you show me yours I'll show you mine again

Answer 56

c = square root of 797 is 28.2

h = 2 square root 286 is 16.9

Is this what we are doing?

Answer 57

Am I getting close. I know the answer is in the 20's, correct?

Answer 58

c is what you're solving for, so that's the answer

Answer 59

So
2 square root 286 squared + 15 squared = c^2

Answer 60

I do that?

Answer 61

572 + 225 = 797

Answer 62

So the answer is 28.2?

Answer 63

@G-unit

Answer 64

Yeah that's the answer

Answer 65

Well I have answer choices, and thats not an answer choice..

Answer 66

@G-unit

Answer 67

Then I probably made a mistake in my math above but I showed you all the steps. Let's go through it again, I'll do it neatly this time.

Answer 68

Okay. One step #1

Answer 69

@G-unit

Answer 70

This is the lateral area of a cone.

\[A_L = \pi*r*\sqrt{h^2 + r^2}\]



\[A_L\] is the lateral surface area, which we have. It's 555pi cm^2
We'll take out the cm^2 since it's unimportant for now

And remember our radius is 15, and that's the r

\[555 \pi = \pi*15*\sqrt{h^2+15^2}\]
\[555 \pi = 15\pi*\sqrt{h^2+225}\]

Then divide both sides by 15pi

\[37 = \sqrt{h^2+225}\]

Square both sides

\[1369 = h^2 + 225\]

Subtract 225 from both sides
\[1144 = h^2 \]

Square both sides

h = 33.82


That's the "height" you can look at the image