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alainabbyboo22

  • 3 years ago

Find the volume of a cone with radius 30 in and slant height 50 in. A. 3769.91 in3 B. 3768 in3 C. 113040 in3 D. 37699.11 in3

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  1. alainabbyboo22
    • 3 years ago
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    can someone help me out here ? i keep trying to solve it but i'm doing something wrong here . @nubeer

  2. nubeer
    • 3 years ago
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    hmm can you tell me the formula for vol of cone?

  3. alainabbyboo22
    • 3 years ago
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    1/3 n r^2 h ?

  4. nubeer
    • 3 years ago
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    |dw:1352739974313:dw|

  5. nubeer
    • 3 years ago
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    volume = 1/3* pi *r^2*h|dw:1352740094367:dw| can you find h?

  6. alainabbyboo22
    • 3 years ago
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    this is what i got for my answer . 47123.8898038

  7. nubeer
    • 3 years ago
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    nop you used 50 in calculations.. as its not the height in this case.. can u see the diagram i drew?

  8. alainabbyboo22
    • 3 years ago
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    yes but now i'm confused on what to do . can you type the equation for me and i will solve ?

  9. nubeer
    • 3 years ago
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    well u first have to find the h.. h is the perpendicular height and its not given.. formula for cone is this. volume = 1/3* pi *r^2*h

  10. nubeer
    • 3 years ago
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    maybe you can do your steps here so i can point your mistake.

  11. alainabbyboo22
    • 3 years ago
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    i did : 1/3 * pi * 30^2 * 50

  12. nubeer
    • 3 years ago
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    ok.. half is right .. the place where u had put 50 that is wrong. its not 50

  13. alainabbyboo22
    • 3 years ago
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    what would i put there then ?

  14. nubeer
    • 3 years ago
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    ok.. would you able to see the picture if i draw here for u? because i posted pictures above but no respone about that from you.

  15. nubeer
    • 3 years ago
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    so i am not sure if you are able to see pictures or something wrong.

  16. nubeer
    • 3 years ago
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    |dw:1352740718104:dw|

  17. nubeer
    • 3 years ago
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    ok can you see the picture now i just posted?

  18. alainabbyboo22
    • 3 years ago
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    okay i see it . but what am i supposed to do ?

  19. alainabbyboo22
    • 3 years ago
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    30 * 50 ?

  20. nubeer
    • 3 years ago
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    do u see the "h" with the dotted line?

  21. alainabbyboo22
    • 3 years ago
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    yes

  22. nubeer
    • 3 years ago
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    ok find the value of "h" by Pythagoras theorem.

  23. alainabbyboo22
    • 3 years ago
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    so 50^2 + 30 ^2 = c^2 ?

  24. nubeer
    • 3 years ago
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    not exactly.. the slanting height is "c" the base is "a" and height is "b"..

  25. nubeer
    • 3 years ago
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    |dw:1352741077853:dw|

  26. nubeer
    • 3 years ago
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    so c^2=a^2+b^2 c=50, a= 30 , b= h can you find h now?

  27. alainabbyboo22
    • 3 years ago
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    1.6

  28. nubeer
    • 3 years ago
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    nooo.. 50^2 - 30^2 = h^2

  29. alainabbyboo22
    • 3 years ago
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    1600^2

  30. nubeer
    • 3 years ago
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    yes h^2 = 1600.. now take square root to find h.

  31. alainabbyboo22
    • 3 years ago
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    40

  32. nubeer
    • 3 years ago
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    good.. this is your h now.. volume = 1/3* pi *r^2*h h=40, r =30 now plug it in formula.

  33. alainabbyboo22
    • 3 years ago
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    A is my answer !!

  34. nubeer
    • 3 years ago
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    yes its A :)

  35. alainabbyboo22
    • 3 years ago
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    woops just double checked that ! its D . my bad !

  36. nubeer
    • 3 years ago
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    lol.. sorry my bad too.. :P

  37. alainabbyboo22
    • 3 years ago
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    haha its all good ! it just made sense but then i looked at my answer again and i'm like wait a minute .. lol thank you for helping me !

  38. nubeer
    • 3 years ago
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    lol you are most welcome anytime :)

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