Results 1 to 8 of 8

Math Help - Word Problems

  1. #1
    Junior Member
    Joined
    Aug 2009
    From
    America
    Posts
    29

    Word Problems

    a.) A water tank has the shape of a cone (like an ice cream cone without ice cream). The tank is
    10m high and has a radius of 3m at the top. If the water is 5m deep (in the middle) what is
    the surface area of the water?

    b.) A kite is 100m above the ground. If there are 200m of string out what is the angle between the
    string and the horizontal. (Assume that the string is perfectly straight.)

    Thanks in advance
    Last edited by saar4ever; August 24th 2009 at 06:46 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by saar4ever View Post
    a.)
    b.) A kite is 100m above the ground. If there are 200m of string out what is the angle between the
    string and the horizontal. (Assume that the string is perfectly straight.)

    vertical = 100 m , hypothenus = 200 m

    sin a = 100/200

    a=arcsin 1/2

    a=30 degrees .
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Aug 2009
    From
    America
    Posts
    29
    thanks just got a.) left its pretty hard been trying it for over 2 hours dunno how to find radius at halfway the cone is it simply 1.5 radius? or more complicated?
    if it is 1.5 radius then pie r squared is 3.1415 times 1.5 squared which is = to 7.069 is that correct surface area for a.)?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Aug 2009
    Posts
    9

    Part b

    part b is easy. using your soh cah toa rule, u can use the soh part which is sinθ=o/h where o=opposite which is 100 and h=hypotenuse which equals 200 since there is 200m of string. therefore;
    sinθ=o/h
    sinθ=100/200
    sinθ=0.5
    θ=sin^(-1)x0.5
    i'll let you figure out the answer:P
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by saar4ever View Post
    a.) A water tank has the shape of a cone (like an ice cream cone without ice cream). The tank is
    10m high and has a radius of 3m at the top. If the water is 5m deep (in the middle) what is
    the surface area of the water?

    first of all draw a cone , then you will see clearly . Now note that the radius of the water, r is different from the radius on top of the cone .

    By similar triangles , 3/10=r/5 .... r=3/2

    so the surface area of the water = \pi(\frac{3}{2})^2+\pi(\frac{3}{2})l ,
    you can find the l using phythagoras .
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Aug 2009
    From
    America
    Posts
    29
    isnt the answer just
    \pi(\frac{3}{2})^2
    why did u add
    +\pi(\frac{3}{2})l
    does the question ask for the side area of water?
    if yes then ur version is correct
    then the answer is:
    31.668 right?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by saar4ever View Post
    isnt the answer just
    \pi(\frac{3}{2})^2
    why did u add
    +\pi(\frac{3}{2})l
    does the question ask for the side area of water?
    if yes then ur version is correct
    \pi r^2 is the top part of the water and \pi rl is the curved surface area of the water . I don see why this part don exist .
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Junior Member
    Joined
    Aug 2009
    From
    America
    Posts
    29
    Quote Originally Posted by mathaddict View Post
    \pi rl is the curved surface area of the water . I don see why this part don exist .
    I forgot that part existed . . .
    thx for the reminder
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. word problems >_<
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 14th 2011, 07:35 PM
  2. Problems with integration word problems
    Posted in the Calculus Forum
    Replies: 5
    Last Post: April 25th 2010, 05:39 PM
  3. Word Problems
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: November 6th 2009, 12:01 PM
  4. Max/min word problems!
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 26th 2009, 06:54 AM
  5. how do u do these word problems?
    Posted in the Pre-Calculus Forum
    Replies: 6
    Last Post: March 29th 2008, 02:54 PM

Search Tags


/mathhelpforum @mathhelpforum