Question

What is the approximate volume of a cone with a height of 9 ft and radius of 3 ft?

Use 3.14 to approximate pi, and express your final answer to the nearest tenth.
@phi

Answer 1

write down the formula for the volume of a cone
then replace r with 3 and h with 9
can you do that ?

Answer 2

V=1/3TTr^2h
V=1/3TT(3)^2(9)

Answer 3

now do the arithmetic.

Answer 4

okay V=1/3TT*9*9
v= 1/3TT*81

Answer 5

keep going

Answer 6

okay um V=1/3*3.14*81
V=1/3*254.34
V=.33*254.34=83.9322

Answer 7

@phi ?????

Answer 8

would it be 84 if you rounded to the nerest tenth

Answer 9

You have the right idea, but you have to be more careful.
you changed 1/3 to 0.33
by .33 is not exactly 1/3

you should do 81/3 first
what do you get?

Answer 10

81/3 would equal ??? um would i have to divide 81 by 3

Answer 11

your problem would be easier if you had done it this way:
\[ \frac{1}{3} \cdot 3 \cdot 3 \cdot 9 \pi \]
I wrote 3^2 as 3*3
next I would divide 3 evenly into 3 that leaves
\[ 3 \cdot 9 \cdot \pi \]
notice how dividing *first* gives you smaller numbers.

now finish the problem

Answer 12

btw, yes 81/3 means 81 divided by 3. you get 27

Answer 13

okay so it would be 81ftTT^3

Answer 14

? 81/3 pi
or
27 pi

Answer 15

okay

Answer 16

now do 27*3.14

Answer 17

so 84.78

Answer 18

would then equal 85 right

Answer 19

to round to the nearest 10th
you would look at the 100th place. if 5 or bigger round up.
here the 10th's place is 7 and the digit to the right is 8. that is 5 or bigger so round up
84.8

Answer 20

okay