Your classmate claims that if you double the radius of a sphere, its surface area and volume will quadruple. What is your classmate’s error? Explain.

QUESTION POSTED AT 03/12/2019 - 04:21 AM

Answered by admin AT 03/12/2019 - 04:21 AM

SA of a sphere is 4πr²   Using a sample of radius 3 the SA would be 36π²
(4πx3²)   If we double the radius and make it 6, the SA would be 144π²
So for Surface area, your classmate is correct.

What about the volume?  V of a Sphere = 4/3 π r³
Again using 3 the Volume of a Sphere with radius 3 = 4/3 π 27
But the volume of a sphere with radius 6 = 4/3 π 216 which is eight times the volume of the smaller sphere. (27 x 8 =216)  So your friend is right about Surface Area but wrong about the volume.
Post your answer

Related questions

Gina’s art teacher mixes 9 pints of yellow paint with 6 pints of blue paint to create green paint. Gina mixes 4 pints of yellow paint with 3 pints of blue paint. Did Gina use the same ratio of yellow paint to blue paint instructed by her teacher? Explain.

I think the answer to that is 8 because i added 9+6=15 then I added 4+3=7 and then I subtracted 15-7=8 just check your answer if I'm correct or not

ANSWERED AT 09/12/2019 - 05:06 AM


QUESTION POSTED AT 09/12/2019 - 05:06 AM

If Yvonne wanted to make 3 dresses that use 4 7/8 yd of fabric each, explain how she could use estimation to make sure she has enough fabric for all of them

I agree. would take the 3 dresses and multiply 5 yards a piece. So she needs a total of 15 yards estimating.

ANSWERED AT 09/12/2019 - 05:06 AM


QUESTION POSTED AT 09/12/2019 - 05:06 AM

Dao has 2 3/8 pounds of hamberger meat je is making 1/4 pound hamburgers does dao have enough meat to make 10 hamburgers explain

So multiply 1/4 by 10 and get 10/4=8/4+2/4=2+1/2=2 and 1/2
is 2 and 3/8 more or equal to than 2 and 1/2
1/2 times 4/4=4/8
he needs 2 and 4/8 and has 2 and 3/8, he is short 1/8 lb
he does not have enough

ANSWERED AT 09/12/2019 - 04:59 AM


QUESTION POSTED AT 09/12/2019 - 04:59 AM

Explain how knowing 1+7 helps you find the sum for 7+1

Knowing 1+7 helps you find the sum of 7+1 because 1+7 and 7+1 is communitive property of addition. Also because 1+7 is the same answer as 7+1. 
Ex:
      1+7=8 
        And
       7+1=8
its the same result.

ANSWERED AT 09/12/2019 - 04:58 AM


QUESTION POSTED AT 09/12/2019 - 04:58 AM

Solve these word problems 1---3 1: A factory processes 1,560 ounces of olive oil per hour. The oil packaged into 24-ounces bottles.How many bottles does the factory fill in one hour 2: A pond at a hotel holds 4,290 gallons of water.The groundskeeper drains the pound at a rate of 78 gallons of water per hour.How long will it take to drain the pound? 3:Explain using partial quotients to divide is similar to using the Distributive proprerty to multiply

1. To do this, you want to divide 1560 by 24.  This gives you 65.  The bottle fills 65 bottles per hour.
2. To do this divide 4290 by 78.  The result is 55.  It would take the groundskeeper 55 hours to drain the pond.  
3. They are similar because you break up pieces of the number and then you combine them.

ANSWERED AT 09/12/2019 - 04:53 AM


QUESTION POSTED AT 09/12/2019 - 04:53 AM

The area of a mirror is 225 square inches, and its width is 13 3/4 inches. Will the mirror fit in a space that is 15 inches by 16 inches? Explain

If you multiply length times width to get area, it's the same with division. You do area divided by length or width. The equation would be 225 divided by 13 3/4. 225/13 3/4= 16.36 inches. 16.36 > 16 inches, so the answer would be no. (The mirrors length and width are 13 3/4 inches by 16 9/25)

ANSWERED AT 09/12/2019 - 04:53 AM


QUESTION POSTED AT 09/12/2019 - 04:53 AM

Can you show how to solve this question? Thomas and Sharlina work on weekends and holidays doing odd jobs around the neighborhood. They are paid by the day, not by the hour. They each earn the same whole number of dollars per day. Last month Thomas earned $184 and Sharlina earned $207 a. How many days did each person work? b. Whatis their daily pay PLEASE EXPLAIN HOW YOU GOT YOUR ANSWER

To find out how much they earned, we need to find the GCF of 184 and 207.

The greatest common factor (GCF) of 184 and 207 is 23.

That means they earn 23 dollars per day. That is your answer for part b.

And Thomas worked 184/23 = 8 days
While Sharlina worked 207/23 = 9 days

That is your answer for part a.

ANSWERED AT 09/12/2019 - 04:51 AM


QUESTION POSTED AT 09/12/2019 - 04:51 AM

Explain how you can find 4 times 754 using two different methods.

Method 1:

4(754)

=4(700+50+4)

=2800 + 200 + 16

=3000+16

=3016

-----------------

Method 2:

4(754)

=4(250+250+250+4)

=1000+1000+1000+16

=3016

ANSWERED AT 09/12/2019 - 04:51 AM


QUESTION POSTED AT 09/12/2019 - 04:51 AM

What is the volume of a right rectangular prism that is 4 yards x 1.5 yards x 8 yards

The answer to that question is 48. All you do is muliply 4*1.5*8=48

ANSWERED AT 09/12/2019 - 04:42 AM


QUESTION POSTED AT 09/12/2019 - 04:42 AM

10 POINTS. 1/7 written as a decimal is 0.142857 (this sequence repeats). What digit occurs in the 2012th spot after the decimal? Please explain.

1/7 = 0.142857142857142857142857142857142857142857142857142857 and so on

the pattern repeats

the first digit is 1
second digit is 4
third digit is 2
fourth digit is 8
fifth digit is 5
sixth digit is 7

and then the seventh digit is 1, and it repeats

so the six digits repeat again and again...

2012/6 = 335 2/6

It has a remainder of 2, which means that the 12th digit will be 4. because that is the second digit. After going 335 times the 6 digit patterns it will stop at the second digit which is 4.

Your answer is 4.

I hope you understood, it was kind of hard to explain :P

ANSWERED AT 09/12/2019 - 04:37 AM


QUESTION POSTED AT 09/12/2019 - 04:37 AM

Find two integers whose sum is -7 ans whose product is 12. Explain how you found the numbers.

-3 + -4 = -7
add the numbers and keep the common sign.
-3 * -4 = 12
since the factors are both negative, the product is positive, when multiplying and/or dividing. 

ANSWERED AT 09/12/2019 - 04:26 AM


QUESTION POSTED AT 09/12/2019 - 04:26 AM

Explain two different waysto find the difference for 12-3

One way: subtract 12-3 =9 
the other way sub in and make equations

ANSWERED AT 09/12/2019 - 04:25 AM


QUESTION POSTED AT 09/12/2019 - 04:25 AM

I just need to find y explain please :p

Rewrite in slope intercept from y=mx+b  y=1-3x+11/3

ANSWERED AT 09/12/2019 - 04:22 AM


QUESTION POSTED AT 09/12/2019 - 04:22 AM

Fifteen children voted for their favorite color. the votes for red and blue together were double the votes for green and yellow together. how did the children vote?

Three At the same time and 1picked y or g and two picked red or b

ANSWERED AT 09/12/2019 - 03:57 AM


QUESTION POSTED AT 09/12/2019 - 03:57 AM

Solomon has $188.He wants to purchase concert tickets fir himself and 5 friends.Each ticket cost $19.Does he have enough money? Explain

he has 188 bucks and 5 friends plus him each cost 19 bucks so divided 19 and 188 equal answer th em divided the answer and 5

ANSWERED AT 09/12/2019 - 03:53 AM


QUESTION POSTED AT 09/12/2019 - 03:53 AM

How can adding doubles help you multiply by 2? will someone please give me an example

OK 2+2+2+2+2+2+2=14 and it's the same as 2×7

ANSWERED AT 08/12/2019 - 10:45 PM


QUESTION POSTED AT 08/12/2019 - 10:45 PM

Explain the steps on 941 divided by 2

The answer of 941 ÷2 is 470.5

ANSWERED AT 08/12/2019 - 04:57 PM


QUESTION POSTED AT 08/12/2019 - 04:57 PM

The area of a rectangular picture frame is 30 1/3 square inches. The length of the frame is 6 1/2. Find the width of the width

Answer:

\texttt{Width of rectangular picture frame}=4\frac{2}{3}inch

Step-by-step explanation:

The area of a rectangular picture frame is 30 1/3 square inches. The length of the frame is 6 1/2.

\texttt{Length of rectangular picture frame = }6\frac{1}{2}=\frac{6\times 2+1}{2}=\frac{13}{2}inch

\texttt{Area of rectangular picture frame = }30\frac{1}{3}=\frac{30\times 3+1}{3}=\frac{91}{3}inch^2

Area of rectangle = length x width

We have

  \frac{91}{3}=\frac{13}{2}\times \texttt{Width}\\\\\texttt{Width}=\frac{91}{3}\times \frac{2}{13}=\frac{14}{3}=4\frac{2}{3}inch

\texttt{Width of rectangular picture frame}=4\frac{2}{3}inch

ANSWERED AT 08/12/2019 - 04:39 PM


QUESTION POSTED AT 08/12/2019 - 04:39 PM

Jules reads that one pint is equivalent to 0.473 liters.he asks his teacher how many liters there are in a pint.His teacher responds that there are about 0.47 liters in a pint.He asks his parents,and they say there are about 0.5 liters in a pint Jules says they are both correct. How can that be true? Explain your answer

Julie reads that 1 pint is equivalent to 0.472 liters.
First, he asked his teacher how many liters are there in 1 pint and answered 0.47 liters
Then he asked his parents and said 0.5 liters.
They are both correct, why?
becayse the exact value if 0.473 when you round this to its nearest hundredths, the answer would be 0.47 and when you round it to its nearest tenths, the answer will be 0.5. Thus both answers are correct.



ANSWERED AT 08/12/2019 - 04:37 PM


QUESTION POSTED AT 08/12/2019 - 04:37 PM

A painter painted about half a room in half a day. Coley estimated the painter would pain 7 rooms in 7 days. Is Coley's estimate reasonable? Explain

Yes, because the painter painted half a room in half a day and if he were to paint the other half in the other half of the day it would give you one room painted in one whole day.

ANSWERED AT 08/12/2019 - 04:29 PM


QUESTION POSTED AT 08/12/2019 - 04:29 PM

Explain 2 ways to evaluate 15(90-3)

First Way:

15(90-3)

=15(10*9-3)

=15*10*9-15*3

=150*9-45

=1,350-45

=1,305

-----------------

Second Way:

15(90-3)

=15(87)

=15(80+7)

=15(10*8+7)

=15*10*8+15*7

=150*8+(10+5)*7

=1,200+70+35

=1,200+105

=1,305

ANSWERED AT 08/12/2019 - 04:27 PM


QUESTION POSTED AT 08/12/2019 - 04:27 PM

Is The Ratio 35 To 10 Proportional To The Ratio 7 To 5?Explain

No because no matter what u multiply 7:5 u will never get 35:10, they are not equal

ANSWERED AT 08/12/2019 - 04:22 PM


QUESTION POSTED AT 08/12/2019 - 04:22 PM

What are possible dimensions of the area 104 cm

U just find the factors of 104 which are 2, 2, 2 and 13. Then combine them in any way to make 2 numbers
like 2 times 2 times 2 and 13
which would be 8 times 13

ANSWERED AT 08/12/2019 - 04:17 PM


QUESTION POSTED AT 08/12/2019 - 04:17 PM

Please someone help me and explain this question to me (the last question starting with a straw)


Each straw is  4-1/8 inches long.
You have one gigantic piece of straw material, 123-3/4 inches long.
How many straws can you cut it up to make ?

 ===>                    (123-3/4)  divided by  (4-1/8)            straws.

Each one costs  $0.015  to make.
So, once you find the number of short straws you have,
multiply

===>                 (the number of short straws) x ($0.015) .

That'll tell you how much it costs to make all of them. 


Now you know how to do it on your own.
If you don't get  30 straws  and  $0.45 , please try again.

ANSWERED AT 08/12/2019 - 04:01 PM


QUESTION POSTED AT 08/12/2019 - 04:01 PM

Tomas bought a bottle of shampoo that held 10.5 fluid ounces. he uses 1/16 of the shampoo every time he washes his hair. how many ounces of the shampoo are left after he washes his hair 6 times please help because I'm confused with this question and explain clearly too please

Answer

6\frac{9}{16} fluid ounces

Explanation

First, we are going to find the total amount of shampoo he used. We know from a our problem that he uses \frac{1}{16} of the shampoo every time he washes his hair and he washed his hair 6 times, so we just need to multiply the number of times (6) by the amount used every time (\frac{1}{16}) to find how much shampoo he used:

6*\frac{1}{16} =\frac{6}{16} =\frac{3}{8}

We know that he used \frac{3}{8} of the bottle of shampoo. Since the bottle of shampoo held 10.5 fluid ounces, we are going to multiply 10.5 fluid ounces by \frac{3}{8} to find how much fluid ounces he used:

10.5f.oz*\frac{3}{8} =3.9375f.oz

Now, to find the ounces of shampoo left, we just need to subtract the ounces used (3.9375 fluid ounces) by the initial fluid ounces in the bottle of shampoo (10.5 fluid ounces):

10.5f.oz-3.9375f.oz=6.5625f.oz or expressed as a mixed fraction: 6\frac{9}{16} f.oz

We can conclude that there are 6\frac{9}{16} fluid ounces of shampoo left after Tomas washed his hair 6 times.

ANSWERED AT 08/12/2019 - 04:01 PM


QUESTION POSTED AT 08/12/2019 - 04:01 PM

Hat is the area of the shaded part of the figure? A. 144 mm² B. 288 mm² C. 432 mm² D. 720 mm²


1) Striangle = 24*24 = 576 mm^2

2) Ssqare = 12*12 = 144 mm^2

3) Sfigure = 576 - 144 = 432 mm^2

Number C

ANSWERED AT 08/12/2019 - 03:53 PM


QUESTION POSTED AT 08/12/2019 - 03:53 PM

What is the area of the figure? A. 24 km² B. 32 km² C. 40 km² D. 48 km²


1) Striangle = 1/2 * (12-8) * 4 = 1/2 * 4 * 4 = 8 km^2

2) Srectangle = 4 * 8 = 32 km^2

3) Sfigure = 8 + 32 = 40 km^2

Number C

ANSWERED AT 08/12/2019 - 03:53 PM


QUESTION POSTED AT 08/12/2019 - 03:53 PM