Thursday, September 17, 2026

Geometric Challenge

Problem 1623: Two Adjacent Squares and Bounding Square Proof

Share your proof or solution in the comments below.
Target Audience: K-12, Honors Geometry, and College Mathematics Education.

In Problem 1623, we explore two adjacent squares constructed on a straight line. A bounding rectangle circumscribes both squares with its sides aligned parallel and perpendicular to an auxiliary segment. The challenge is to prove using pure triangle congruence that this bounding rectangle is strictly a square, and that its side length L equals the sum of the auxiliary segment length h and the altitude m drawn to it.
Explore the full theorem and illustrated diagram by clicking the image below.

Illustration of Geometry Problem 1623: Two Adjacent Squares and Bounding Square Proof
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2 comments:

  1. Let A' be the point where the extension of AG intersects LK.
    Since △NGB ≡ △A'FG,
    LM = AA' = h + m.
    Furthermore,
    since △NBA ≡ △MAE, LF = h,
    and since △NGB ≡ △KCF, FK = m.
    Therefore, LK = h + m.
    Q is a square with a side length of h + m.

    ReplyDelete
  2. Let AN = u so that GN = h - u

    If AG meets LK at X we have
    Triangles GFX & NBG congruent ASA
    So GX = m and AX = h + m = LM ............(1)

    Triangles AME & ABN are also congruent ASA
    So AM = u
    But Triangles GFX & BNG are congruent ASA
    So XF = h - u which gives
    LF = LX + FX = AM + XF = u + (h -u) = h ...........(2)

    Now since CKF & BNG are congruent ASA
    FK = m ...... (3)
    Hence LK = h + m (from (2) & (3))

    So LM = LK = h + m
    Thus LMJK is a square of side h + m

    Sumith Peiris
    Moratuwa
    Sri Lanka

    ReplyDelete

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