## anonymous 5 years ago if h,s, V be the height, Curved surface area and volume of a cone respectively then 3piVh^3 - s^2h^2 + 9V^2 is: NOTE PI = 22/7 or 3.14

1. anonymous

sstarica do u want options

2. anonymous

you mean $(3\pi Vh)^3 - s^2h^2 + 9V^2$ so what's the problem?

3. anonymous

no sstarica

4. anonymous

it is only h^3

5. anonymous

so you have to solve it

6. anonymous

then why do you have 3 piV multiplied by h?

7. anonymous

i dodn't undeand rst

8. anonymous

you have 3piVh ^3 right?

9. anonymous

yes of course

10. anonymous

you want to solve the equation?

11. anonymous

yes

12. anonymous

but your question is unfortunately unclear, what is excatly that you want?

13. anonymous

SEE i am giving you V= 1/3 * pi * r^2 * h

14. anonymous

lol

15. anonymous

AND S = pi^2r^2(root of (r^2 + h^2))

16. anonymous

so you don't know the answer of only 8th standard

17. anonymous

no now, I got you. :)

18. anonymous

oh k

19. anonymous

20. anonymous

excuse me, you're the one who asked for help, why are you being so boiled up? It's rude, please be polite.

21. anonymous

okey

22. anonymous

all you have to do is substitute V and S in the equation and simplify.

23. anonymous

THIS IS THE PROBLEM THAT I M FACING THE ANSWER IS NOT IN OPTIONS

24. anonymous

and when you do that you get in the end.$\pi^2r^2h^4 - 4\pi r^4h^2(r^2 + h^2) + 1/3 \pi r^2h$

25. anonymous

yes i did that

26. anonymous

ofcourse you won't get it corret in the first place, try again. What are the options, tell me?

27. anonymous

okey i m giving the options

28. anonymous

1) option - 2

29. anonymous

2) option - 0

30. anonymous

3) option - 2pi

31. anonymous

4) option - 3(pi)^2

32. anonymous

I've made a mistake, in the end of the answer I gave you above it's supposed to be $3\pi r^2h$ and note 1/3 pir^2h

33. anonymous

not*

34. anonymous

35. anonymous

here the solution is : first you'll substitute the given in the formula and you will end up with this: $\pi^2 r^2h^4 - 4 \pi^2r^4h^2(r^2 + h^2) + \pi^2r^4h^2$ then simplify, it's a long step but in the end you will end up with : $-3\pi^2r^2h^4 - 3\pi^2r^2h^2$ = $-3\pi^2h^2(r^2h^2 - r^2h^2)$ = $-3\pi^2h^2$ x 0 = 0 That's it :)

36. anonymous

wait that's wrong >_<

37. anonymous

this has caused me a headache._.