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Math Help - arghh!!! please help - new to this hope im posting correctly

  1. #1
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    arghh!!! please help - new to this hope im posting correctly

    Points A (3,1), B(-1,-11), C(-5,9)

    what the slope that passes through A and B

    whats the co-ordinates of the midpoint of the line segment AB

    whats the equation of the perpendicular bisector of AB

    ?? show that the line corresponding to the parametric equations

    x = t - 14
    y = -1/3t
    is the same as the perpendicular bisector of AB

    what is the equation of the perpendicular bisector of the line segment AC

    from the answers of the above find the centre of the circle that passes through a b c

    whats the radius of this circle

    what the equation of this circle

    any help to any of the above would be extremely appreciated
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  2. #2
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    Quote Originally Posted by loes View Post
    Points A (3,1), B(-1,-11), C(-5,9)

    what the slope that passes through A and B
    Plug the two points into slope formula.

    Quote Originally Posted by loes View Post
    whats the co-ordinates of the midpoint of the line segment AB
    Plug the two points into the Midpoint Formula.

    Quote Originally Posted by loes View Post
    whats the equation of the perpendicular bisector of AB
    How are perpendicular slopes related? Use this relationship to use the slope found above to find the perpendicular slope.

    Then use the midpoint and this slope to find equation of the bisector. It would probably be simplest to start with the point-slope formula.

    Quote Originally Posted by loes View Post
    ?? show that the line corresponding to the parametric equations

    x = t - 14
    y = -1/3t
    is the same as the perpendicular bisector of AB
    Solve the first equation for "t=", and plug this into the second equation. Simplify, and compare.

    Quote Originally Posted by loes View Post
    what is the equation of the perpendicular bisector of the line segment AC
    Follow the same procedure as above: find the midpoint, find the slope, find the perpendicular slope, and then find the line equation.

    Quote Originally Posted by loes View Post
    from the answers of the above find the centre of the circle that passes through a b c
    The two line equations form a system of equations. Solve the system to find the intersection point, and thus the center.

    Quote Originally Posted by loes View Post
    whats the radius of this circle
    Plug the center and any of the three given points on the circle into the Distance Formula.

    Quote Originally Posted by loes View Post
    what the equation of this circle
    Plug the center (h, k) and the radius r into the center equation (x - h)^2 + (y - k)^2 = r^2.

    If you get stuck, please reply showing how far you have gotten. Thank you!
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