Results 1 to 3 of 3

Math Help - mirror height

  1. #1
    Senior Member
    Joined
    Jan 2007
    Posts
    476

    mirror height

    A person whose eyes are 1.70 m above the floor stands in front of a plane mirror. The top of her head is 0.15 m above her eyes.

    (a) What is the height of the shortest mirror in which she can see her entire image?
    m

    (b) How far above the floor should the bottom edge of the mirror be placed?
    m


    need help, please help by showing the setup or work this one out please.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,812
    Thanks
    116
    Quote Originally Posted by rcmango View Post
    A person whose eyes are 1.70 m above the floor stands in front of a plane mirror. The top of her head is 0.15 m above her eyes.

    (a) What is the height of the shortest mirror in which she can see her entire image?
    m

    (b) How far above the floor should the bottom edge of the mirror be placed?
    m
    I've attached a sketch.

    You will easily see that the minimum length of the mirror must be 0.925 m and
    that the bottom edge of the mirror must be placed 0.85 m above the floor.

    You also will see that the distance from the mirror doesn't matter.
    Attached Thumbnails Attached Thumbnails mirror height-person_vorspiegel.gif  
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member
    Joined
    Jan 2007
    Posts
    476
    Thanks for the diagram, it makes it so much easier to see when its looked at that way.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Locating the mirror and detector
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: May 24th 2010, 09:21 PM
  2. mirror equation...hate them!!
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: May 9th 2009, 05:33 AM
  3. plane mirror
    Posted in the Geometry Forum
    Replies: 3
    Last Post: December 1st 2008, 07:55 PM
  4. mirror and beam reflection
    Posted in the Math Topics Forum
    Replies: 3
    Last Post: March 2nd 2008, 11:06 PM
  5. Paraboloid Mirror
    Posted in the Pre-Calculus Forum
    Replies: 7
    Last Post: October 30th 2007, 11:33 PM

Search Tags


/mathhelpforum @mathhelpforum