Question

Find the surface area of the cone to the nearest tenth.

Answer 1

A. 203 cm2

B. 1341.5 cm2

C. 747.7 cm2

D. 213.5 cm2

Answer 2

here is the formula
http://math.about.com/od/formulas/ss/surfaceareavol_2.htm

Answer 3

can you match your numbers to the variable names in the formula?

Answer 4

i got 441 pi but thats not right..

Answer 5

i did 1/3 pi 7^2 27 .. what did i do wrong?

Answer 6

ooops i did the volume formula thats why!

Answer 7

this time i got 238 thats still not right ...

Answer 8

\[ area = \pi r^2 + \pi r s\]
r is 7 and s is 27

is that what you started with ?

Answer 9

it looks like you did not multiply by pi

Answer 10

im still getting 238 -_-

Answer 11

i did pi*7^2 + pi 7 * 27

Answer 12

238 is r^2 + r*s
the formula is pi r^2 + pi*r*s
or pi*(r^2 + r*s)

Answer 13

7*7 is 49
7*27 is 189
add together you get 238
no pi

Answer 14

can you figure out how to do it?

Answer 15

okay i get that

Answer 16

for pi * 7^2 i got 153.86

Answer 17

for pi * 7 * 27 i got 593.46

Answer 18

so would it be C ???

Answer 19

yes, I thought you figured it out already.

Answer 20

okay so it is C?

Answer 21

btw, you should not round to only 2 decimals, because your answer is slightly off.
if you used all the digits the calculator gives you you get
747.6990516 which rounds to 747.7

Answer 22

okay thank you so much for your help!!!

Answer 23

yw