## ErinWeeks Group Title Find the surface area of the cone to the nearest tenth. one year ago one year ago

1. ErinWeeks Group Title

2. ErinWeeks Group Title

A. 203 cm2 B. 1341.5 cm2 C. 747.7 cm2 D. 213.5 cm2

3. phi Group Title

4. phi Group Title

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

5. ErinWeeks Group Title

i got 441 pi but thats not right..

6. ErinWeeks Group Title

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

7. ErinWeeks Group Title

ooops i did the volume formula thats why!

8. ErinWeeks Group Title

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

9. phi Group Title

$area = \pi r^2 + \pi r s$ r is 7 and s is 27 is that what you started with ?

10. phi Group Title

it looks like you did not multiply by pi

11. ErinWeeks Group Title

im still getting 238 -_-

12. ErinWeeks Group Title

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

13. phi Group Title

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

14. phi Group Title

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

15. phi Group Title

can you figure out how to do it?

16. ErinWeeks Group Title

okay i get that

17. ErinWeeks Group Title

for pi * 7^2 i got 153.86

18. ErinWeeks Group Title

for pi * 7 * 27 i got 593.46

19. ErinWeeks Group Title

so would it be C ???

20. phi Group Title

yes, I thought you figured it out already.

21. ErinWeeks Group Title

okay so it is C?

22. phi Group Title

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

23. ErinWeeks Group Title

okay thank you so much for your help!!!

24. phi Group Title

yw