Results 1 to 6 of 6

Math Help - question with the answer

  1. #1
    Member
    Joined
    Sep 2008
    Posts
    120

    question with the answer

    A women entering an outside glass elevator on the ground floor of a hotel glances up to the top of the building across the street and notices that the angle of elevation is 48 degrees. She rides the elevator up 60 feet and finds the angle of elevation is 32 degrees. How tall is the building across the street?

    is it 209 feet?

    [x] / [sin(32)] = [x+60] / [sin(48)]

    cross multiply and solve for x then add that to 60 to get the height, is that correct?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,234
    Thanks
    27
    It seems like you are equating ratios here, is this because you want to use similar triangles?

    Are the triangles in this scenario actually similar?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Sep 2008
    Posts
    120
    Quote Originally Posted by pickslides View Post
    It seems like you are equating ratios here, is this because you want to use similar triangles?

    Are the triangles in this scenario actually similar?
    Well, the worksheet tells me to use the Law of Sines. The triangles cannot be similar since I have 2 angles (the angles of elevation) have different measurements. To be similar they have all angles similar.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    Quote Originally Posted by IDontunderstand View Post
    A women entering an outside glass elevator on the ground floor of a hotel glances up to the top of the building across the street and notices that the angle of elevation is 48 degrees. She rides the elevator up 60 feet and finds the angle of elevation is 32 degrees. How tall is the building across the street?

    is it 209 feet?

    [x] / [sin(32)] = [x+60] / [sin(48)]

    cross multiply and solve for x then add that to 60 to get the height, is that correct?
    make a sketch ... make a sketch ... make a sketch

    I'd use the law of sines to find the distance from the elevator bottom to the building top, then use the large right triangle to find the building height.

    I get about 137' for the height.

    btw ... did I say to make a sketch?
    Attached Thumbnails Attached Thumbnails question with the answer-bldgprob1.jpg  
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Sep 2008
    Posts
    120
    My picture was all wrong. I see what I did wrong. Thanks
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Apr 2005
    Posts
    14,973
    Thanks
    1121
    Skeeter, do you think maybe it would be a good idea to make a sketch?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: November 7th 2011, 03:27 PM
  2. question about answer to fourier series question
    Posted in the Advanced Math Topics Forum
    Replies: 11
    Last Post: February 9th 2011, 12:29 PM
  3. Stats question. is there enough info to answer the question
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: April 5th 2009, 10:23 PM
  4. Please help us answer this 11+ question
    Posted in the Algebra Forum
    Replies: 3
    Last Post: December 29th 2008, 07:29 AM
  5. Replies: 1
    Last Post: August 29th 2008, 10:17 AM

Search Tags


/mathhelpforum @mathhelpforum