Question

A cone has a radius of 15 cm and a volume of 540 cm3. What is the volume of a similar cone with a radius of 10 cm?
54 cm3
240 cm3
160 cm3
360 cm3

Answer 1

I think the answer is 240.

Answer 2

please help, will give medal out to best answer.

Answer 3

If two solids are similar, then their corresponding sides are all proportional. The ratio of their surface areas is the side ratio squared and note that the ratios of the areas does not give the actual surface areas. The volume ratio for the two solids is the side length ratio raised to the third power. Again, this is not the solids' volume, only the ratio of the volumes.
https://www.brightstorm.com/math/geometry/similarity/similarity-and-volume-ratios/

by that description... that means if they give you the ratio of the lengths to be a/b
then the ratio of the volumes would be (a/b)^3 or a^3/b^3

so they gave you 10/15 as the lengths ratio
and so what would be (10/15)^3 = ?

Answer 4

that would equal 0.29.

Answer 5

I was thinking of keeping it as a fraction so we can do a ratio
like (10/15)^3 = (2/3)^3 = 8/27

so ratio
8 x
--- = --- solve for x
27 540

Answer 6

x is 160

Answer 7

yeah... and that's what I think the answer should be... unless you were taught differently xP cuz I just taught myself the concept without a teacher so idk if I'm right ;)

Answer 8

ok, thanks so much. I think I understand now how to do that from now on. could you help me with some other questions? normally I just do it myself but this test is a lot of my grade and most of the stuff i'm ok with but some i'm not very sure how to do them or the answer of them.

Answer 9

I'll just try to ignore that you told me that it's a test (since helping on tests is cheating) and I'll see if I can help xD

Answer 10

k thanks so much, just give me like 2 minutes to get them ready.

Answer 11

3. Which of the following are considered skew lines?
http://tinypic.com/view.php?pic=k9vx8p&s=8#.U2vjG1e8hyU (1 point)
AC and CD
DH and BF
EG and FH
AE and GH

Answer 12

I'll submit them one at a time if thats ok?

Answer 13

Two nonparallel lines in space that do not intersect are called Skew lines.
http://www.icoachmath.com/math_dictionary/skew_lines.html

Answer 14

idk whut that means but ok xD

Answer 15

http://tinypic.com/view.php?pic=fwjfvo&s=8#.U2vm21e8hyU
7. Which solid does the net form?

(1 point)
square pyramid
triangular prism
triangular pyramid
cube

Answer 16

well if you think about folding it up mentally...
then

Answer 17

I think d is the answer for the skew lines question and a is the answer to this one

Answer 18

correct and correct :) good job! :D

Answer 19

ok thanks, now i'll submit the next one.

Answer 20

http://tinypic.com/view.php?pic=2vkjmo2&s=8#.U2vpCFe8hyU
16. The cones below are similar, although not drawn to scale.

What is the length of the radius of the larger cone? (1 point)
5 ft
6 ft
7 ft
8 ft

Answer 21

5 x
-- = --
15 18

Answer 22

the answer is 6

Answer 23

http://tinypic.com/view.php?pic=15xl8id&s=8#.U2vr8Fe8hyU
15.
What is the length of the diagonal for the given rectangular prism to the nearest whole unit?

Answer 24

Am i right about number 16?

Answer 25

erm...
use pythagorean theorem to find diagonal produced by legs 12 and 4
then use the value that you get and 9 as the legs for another right triangle...

Answer 26

yes :)

Answer 27

I get 15.52 after doing what you said which would mean the answer is 16, is that right?

Answer 28

12^2 + 14^2 = 340
340 + 9^2 = 421
square root of 421 = 20.518

Answer 29

ok I understand, thanks so much for your help, there is only three more if you don't mind helping me finish.

Answer 30

http://tinypic.com/view.php?pic=fbmcr8&s=8#.U2vw0le8hyU
8. What is the surface area of the given figure?

(1 point)
2,520 cm2
2,792 cm2
4,080 cm2
2,280 cm2

Answer 31

find the area of each side and add it all together
you have three rectangles and two right triangles
area of a rectangle = length * width
area of triangle = (1/2) base*height

Answer 32

I'm sorry but this is one thing i am terrible at, I don't even see how to do this besides the first triangle with 24 as the base and 10 the height. Can you help me understand?

Answer 33

or could you help me with this one while i try to understand the other one?
9.
Use the net to find the approximate surface area of the cylinder to the nearest square meter.
http://tinypic.com/view.php?pic=rjr5sx&s=8#.U2vxE1e8hyU (1 point)

440 m2
314 m2
283 m2
214 m2

Answer 34

the left rectangle is 10 by 34
the top rectangle is 26 by 34
the bottom rectangle is 24 by 34
and you're right about the triangles :)

Answer 35

the surface area of a cylinder is base circle + base circle + rectangle
area of base circle = pi*radius^2 = pi*(5)^2 = ?
area of rectangle = length*width = length*circumference of circle
= length*2*pi*radius = 9*2*pi*5 = ?

Answer 36

for number 8 the answer is d, now I'll work on the other one.

Answer 37

correct :)

Answer 38

my comp just crashed i'm sorry the answer is a

Answer 39

yes :)

Answer 40

Find the lateral area of the square pyramid.
http://tinypic.com/view.php?pic=16gnbyp&s=8#.U2v6ole8hyU
square pyramid (3 points)

Answer 41

erm sorry but idk wut lateral area is... o.o

Answer 42

oh ok, that's fine, may need your help on a couple other answers cause i lost all my answers including ones that i didn't ask you.