Results 1 to 3 of 3

Math Help - Slopes Help

  1. #1
    Senior Member
    Joined
    Jul 2006
    From
    Shabu City
    Posts
    381

    Slopes Help

    Slopes

    1.) Using slopes, determine which of the set of three points lie on a straight line:
    (-1,-2),(6,-5),(-10,2)


    2.) The line segment drawn from P(x,3) to (4,1) is perpendicular to the segment drawn from (-5,-6) to (4,1). Find the value of x.

    Thanks a bunch
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,901
    Thanks
    329
    Awards
    1
    Quote Originally Posted by ^_^Engineer_Adam^_^ View Post
    2.) The line segment drawn from P(x,3) to (4,1) is perpendicular to the segment drawn from (-5,-6) to (4,1). Find the value of x.
    To find the slope of a line use the equation:
    m = \frac{y_2 - y_1}{x_2 - x_1}

    Slopes that are perpendicular are negative inverses:
    m_2 = -\frac{1}{m_1}

    -Dan
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,829
    Thanks
    123
    Quote Originally Posted by ^_^Engineer_Adam^_^ View Post
    Slopes

    1.) Using slopes, determine which of the set of three points lie on a straight line:
    (-1,-2),(6,-5),(-10,2)


    2.) The line segment drawn from P(x,3) to (4,1) is perpendicular to the segment drawn from (-5,-6) to (4,1). Find the value of x.

    Thanks a bunch
    Hello,

    to 1.) You have three points: A(-1, -2), B(6, -5), C(-10, 2).

    If the slope between A and B is the same as the slope between B and C, then the three points lie on a straight line:
    s means slope:

    s_{AB}=\frac{-2-(-5)}{-1-6}=\frac{3}{-7}


    s_{BC}=\frac{2-(-5)}{-10-6}=\frac{7}{-16}

    Both slopes are not equal therefore the three points don't lie on a straight line.

    to 2.) You have 3 points: P(x, 3), Q(4, 1) and B(-5, -6)

    a) Calculate the slope between Q and B:
    s_{QB}=\frac{1-(-6)}{4-(-5)}=\frac{7}{9}. Thus the perpendicular direction is: -9/7 (have a look at topsquark's post!)

    The slope between P and Q should be equal to this perpendicular slope:

    s_{PQ}=\frac{3-1}{x-4}=-\frac{9}{7}. Solve for x.

    (I've got x = 22/9)

    EB
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. slopes
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: October 2nd 2008, 09:36 AM
  2. Slopes of triangles???
    Posted in the Algebra Forum
    Replies: 4
    Last Post: December 27th 2007, 07:22 PM
  3. help with slopes!
    Posted in the Pre-Calculus Forum
    Replies: 7
    Last Post: May 3rd 2007, 02:59 PM
  4. slopes
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: February 22nd 2007, 08:54 AM
  5. need help on Slopes
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: November 18th 2006, 10:05 AM

Search Tags


/mathhelpforum @mathhelpforum