Question

http://prntscr.com/b6x5ug
9 I got
V=123 in terms of pi
SA=81 in terms of pi

This is the incorrect. The answers should be 36 pi for volume and 36 pi for SA, but I'm not sure why I'm getting the incorrect answer.

Answer 1

\(\Large V_{sphere} = \dfrac{4}{3} \pi r^3\)

Answer 2

\(\Large A_{sphere} = 4 \pi r^2\)

Answer 3

If the diameter is 9 m, what is the radius?

Answer 4

4.5

Answer 5

Good.
Let's do the volume first.
Now cube 4.5.
What is \(4.5^3\) ?

Answer 6

91.125

Answer 7

Correct.
Now multiply the number by 4 and divide by 3 to take care of the fraction 4/3.

Answer 8

121.5

Answer 9

Correct.
Since that number needs to be multiplied by pi, the answer is 121.5π.

The problem wants the number part rounded off to a whole number, so round off 121.5 to a whole number.

Answer 10

http://prntscr.com/b7n7ip

Weird, it says the answer is 36 for volume

Answer 11

According tot eh instructions you posted, the volume should be \(122\pi~m^3\).
Your answer of 123pi was pretty close.

Answer 12

Ready for the area?

Answer 13

Yes I am!
@mathstudent55

Answer 14

We use the formula above for area.
We need to square the radius, and we already know the radius is 4.5 m.
What is \(4.5^2\)

Answer 15

81

Answer 16

@mathstudent55

Answer 17

4.5^2 = 20.25
Then you multiply by 4, so you get 81.
Then multiply by pi to get \(81 \pi\)

Answer 18

The area is \(81\pi ~m^2\)

Answer 19

Thank you so much!

Answer 20

The answer has to have pi in it.
The answer is not 81 in terms of pi.
The answer is 81pi

Answer 21

You're welcome.

Answer 22

Would you help me with two other questions revolving around this subject?

Answer 23

sure
pls start a new post for each new question