A Circle Inscribed in an Isosceles Triangle

  • A Circle Inscribed in an Isosceles Triangle


    PoW ID: 735

    6th to 8th, High School, Geometry, Geometry, Geometry Library

    Problem Print

    This problem was sent to me by Ilmar Vitsut, who is a geometry teacher at Viewpoint High School in Calabasas, California. He and I solved it different ways, so I am curious how other people will do it.

    Find the radius of a circle inscribed in an isosceles triangle with sides 12, 12, and 8.

    Answer Check

    Show Answer

    The radius of the circle is 2√2.

    If your answer doesn't match ours,

    • do you have the right definition for "inscribed"? Try this applet in our Math Tools library.
    • did you draw a picture and label it with everything you know?
    • and you did remember that tangents to a circle from the same point are equal in length?

    If any of those ideas help you, you might revise your answer, and then leave a comment that tells us what you did. If you're still stuck, leave a comment that tells us where you think you need help.

    If your answer does match ours,

    • and you used two different method, which did you think was easier? Why?
    • did you make any mistakes along the way? If so, how did you find them?
    • are there any hints you would give another student?

    Revise your work if you have any ideas to add. Otherwise leave us a comment that tells us how you think you did - you might answer one or more of the questions above.

    Teacher Materials