Results 1 to 8 of 8

Math Help - help with quadratic word problems?

  1. #1
    Junior Member
    Joined
    Jul 2009
    Posts
    36

    help with quadratic word problems?

    ladder location. A ladder leaning against the wall of a building is 13ft long. The distance from the building to the bottom of the ladder is 7ft less than the distance (d) to the top of the ladder. Find the distance d to the top of the ladder and the distance from the building to the bottom of the ladder.

    can someone solve this using a quadratic equation and be able to tell me the distance to top of ladder and distance from building?

    and another one is

    Rectangular envelope. The length of a rectangular envelope is 4 in greater than its width. The area of the envelope is 96 in^2. Find the length and the width of the envelope using a quadratic equation.

    Thx in advanced. im lost with these word problems
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member Stroodle's Avatar
    Joined
    Jun 2009
    Posts
    367
    For the first one, using Pythagorus' Theorem, you have:

    13^2=d^2+(d-7)^2

    and for second one you should get:

    96=w(w+4)

    Do you need help from there?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jul 2009
    Posts
    36
    yes i do, also i thought it was suspose to be in the form of
    Follow Math Help Forum on Facebook and Google+

  4. #4
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by wonderd View Post
    yes i do, also i thought it was suspose to be in the form of
    You're meant to use algebraic manipulation (such as the binomial theorem) to get it into that form

    d^2+(d-7)^2 = 13^2

    d^2+d^2-14d+49=169

    2d^2-14d-120=0

    d^2-7d-60=0

    (Hint: This one factorises)
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Jul 2009
    Posts
    36
    can i just take and use the quadratic formula to get the 2 answers?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by wonderd View Post
    can i just take and use the quadratic formula to get the 2 answers?
    You can
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Junior Member
    Joined
    Jul 2009
    Posts
    36
    what would be in the form of
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Senior Member Stroodle's Avatar
    Joined
    Jun 2009
    Posts
    367
    Not quite:

    96=w(w+4)

    96=w^2+4w

    w^2+4w-96=0

    Have a look here: http://www.purplemath.com/modules/index.htm under the "Intermediate Algebra Topics" for more info on how to expand, factorise, and solve quadratic equations.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Quadratic word problems.
    Posted in the Pre-Calculus Forum
    Replies: 5
    Last Post: September 8th 2008, 06:31 PM
  2. Quadratic Word problems ?
    Posted in the Algebra Forum
    Replies: 1
    Last Post: May 29th 2008, 08:40 PM
  3. Quadratic word problems.
    Posted in the Algebra Forum
    Replies: 4
    Last Post: October 2nd 2007, 10:54 PM
  4. Quadratic word problems
    Posted in the Algebra Forum
    Replies: 1
    Last Post: September 23rd 2007, 12:09 PM
  5. Quadratic Word Problems
    Posted in the Algebra Forum
    Replies: 5
    Last Post: September 23rd 2007, 09:43 AM

Search Tags


/mathhelpforum @mathhelpforum