Results 1 to 3 of 3

Math Help - Question about angle and segment relationships?

  1. #1
    Junior Member
    Joined
    Jan 2008
    Posts
    53

    Question about angle and segment relationships?

    Heres the question: Secants ABC and ADE intersect at point A outside the circle. If AC=20, AB=5, AD=4, find AE.

    Okay so i did
    20*5=4*x
    100=4x
    100/4=4x/4
    x=25

    Okay so my question is, is the answer 25 or do i subtract 4 from it?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Feb 2008
    From
    Westwood, Los Angeles, CA
    Posts
    176
    Thanks
    1
    AE is 25. AE (or ADE) is comprised of AD and DE. You found AE (which was asked). AD = 4 and DE = 21.

    Good!
    Follow Math Help Forum on Facebook and Google+

  3. #3
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by eh501 View Post
    Heres the question: Secants ABC and ADE intersect at point A outside the circle. If AC=20, AB=5, AD=4, find AE.

    Okay so i did
    20*5=4*x
    100=4x
    100/4=4x/4
    x=25

    Okay so my question is, is the answer 25 or do i subtract 4 from it?
    Actually, the correct set up is this: If two secants intersect at an external point, the product of the external segment of one secant times the whole secant is equal to the external part of the other secant times the whole secant.

    In other words, by my diagram: AB \cdot AC=AD \cdot AE

    Therefore,

    5\cdot20=4\cdot(4+DE)

    AE=4+DE

    5\cdot20=4(4+DE)

    100=16+4(DE)

    84=4(DE)

    21=DE

    AE=4+DE \Longrightarrow 4+21=25
    Attached Thumbnails Attached Thumbnails Question about angle and segment relationships?-secant.jpg  
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] finding angle in radians of segment??
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: February 19th 2011, 03:15 AM
  2. Right Angle Relationships
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: February 12th 2011, 06:38 PM
  3. Replies: 0
    Last Post: January 25th 2011, 04:06 PM
  4. geometrical relationships question need help
    Posted in the Geometry Forum
    Replies: 4
    Last Post: October 26th 2009, 12:34 PM
  5. Please HELP with Circle segment question
    Posted in the Geometry Forum
    Replies: 2
    Last Post: June 6th 2008, 09:11 AM

Search Tags


/mathhelpforum @mathhelpforum