13 May 2011

18. Square 1X1: Add 4 to create 4 Triangles and 2 Squares

Easy Medium Hard Extreme


Add 4 matchsticks to create a mininum of 4 triangles and exactly 2 squares. The squares don't have to be equal in size, but the triangles must be. All the matchsticks don't have to be flat on the surface.

11 comments:

  1. it's also possible to add a same size square which is 90 degree rotated from the original square and place the new square onto the old one.

    ReplyDelete
    Replies
    1. Thanks, your solution has been included.

      Delete
    2. you mean 45 degrees.

      Delete
    3. and doesn't the question mandate that the match sticks must lay flat on the surface? is placing sticks on top of other sticks (and thereby not being on the surface) allowed?

      Delete
    4. Yes I think Kimi Liu meant 45 degrees. The matchsticks are allowed not to be flat on the surface. It specifically states that in the question.

      Delete
  2. It's impossible, if all sticks have same length.
    When Inner sticks are shorter than outer, can make this shape.

    ReplyDelete
  3. I came up with the same solution Kimi Lui did. You get equilateral triangles and squares that way. It definitely works with tooth pics, not sure about matchsticks, didn't have any.

    ReplyDelete
    Replies
    1. Answer now include both solutions. Thanks.

      Delete
  4. Sorry Dawie ... you specified 4 triangles, and I just noticed the solution Kimi and I came up with technically creates 8 triangles.

    ReplyDelete
  5. I changed the question to a MINIMUM of 4 triangles. Everybody should be happy now!

    ReplyDelete
  6. you can also add two matches parallel to the each diagonal and touching the sides. this creates a square in the center and four triangles and also four pentagons.

    ReplyDelete