Question

the formula for the volume of a sphere is V=4/3pir^3. find the radius, to the nearest hundredth, of a sphere with a volume of 15in^3

Answer 1

Any ideas?

Answer 2

$$\huge V=\frac{4}{3}\pi r^3$$

Answer 3

no i dont im very confused

Answer 4

The volume is given as $$15 in^3$$ and the question asks you to find the radius...

Answer 5

how would you find the radius though

Answer 6

Solve the formula for it.

Answer 7

$$\huge 15=\frac{4}{3}\pi r^3$$

Answer 8

oh okay so do you like multiply it to both sides or osmething

Answer 9

Yes, use the multiplication property of equality...

Answer 10

$$\huge \frac{15}{\frac{4}{3}\pi}= r^3$$

Answer 11

oh okay

Answer 12

so then you just divid 15 by 4/3 right ?

Answer 13

$$\pi \approx 3.14$$

Answer 14

so you times 3.14 by 4/3 correct ?

Answer 15

Yes.

Answer 16

okay so that would be 4.186
so then
\[\frac{ 15 }{ 4.186}=r ^{3}\]

Answer 17

Yes.

Answer 18

so then you divide 15 by 4.186 right

Answer 19

right

Answer 20

okay and then youll get 62.79=r^2

Answer 21

so is that the answer ?

Answer 22

$$\huge r^3=62.79$$

Answer 23

$$\huge\text{" find the radius,r"}$$
$$\huge\text{" to the nearest hundredth,"}$$

Answer 24

$$\huge (r^3)^{\frac{1}{3}}=(62.79)^{\frac{1}{3}}$$

Answer 25

so r= 18.837

Answer 26

to the the nearest hundredths or 0.01 and don't forget the units...

Answer 27

so it would be 19 ?

Answer 28

Nope, are you using a calculator?

Answer 29

yeah i used my phone

Answer 30

Find $$\huge(62.79)^{0.333}$$

Answer 31

so it would be 20.900907

Answer 32

Nope, that is too large.

Answer 33

well thats what my calculator says....

Answer 34

3.97 inches

Answer 35

https://www.google.ca/search?q=calculator&rlz=1C1RNPN_enCA416&oq=calcula&aqs=chrome.1.69i57j0l5.16220j0j7&sourceid=chrome&espv=210&es_sm=122&ie=UTF-8

Answer 36

is the answer ?

Answer 37

Yes, now check the answer in the original equation.

Answer 38

$$\huge V=\frac{4}{3}\pi r^3$$ $$\huge 15=?=\frac{4}{3}\pi (3.97)^3$$

Answer 39

r= 1.53 in