Saturday, July 11, 2026

Geometric Challenge

Problem 1619: Right Triangle Area in terms of Inradius and Hypotenuse

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

Discover an elegant identity connecting the fundamental metrics of a right triangle. In Problem 1619, we explore how the area relates directly to its inradius and hypotenuse: Area = r(r + c).
Click the image below to view the full problem statement and diagram.

Geometry Problem 1619: Right Triangle Area, Inradius, and Hypotenuse
Click for additional details and full diagram.

Proposed Solution
We invite students, teachers, and math enthusiasts to share their proof. Try using geometric area decomposition or metric properties of tangents.

How to contribute:
Post your step-by-step proof in the comments below. Feel free to:
  • Describe the geometric theorems applied.
  • Share a link to your visual construction (GeoGebra, Desmos).
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1 comment:

  1. With the usual notation for any Triangle ABC,

    In the Right Triangle ABC,
    AG = b - r = AF and BE = a - r = BF

    Hence c = AF + BF = a + b - 2r

    So 2r = a +b - c = 2s - 2c
    and s = r + c....(1)

    But A = r.s
    Therefore from (1),

    A = r(r + c)

    Sumith Peiris
    Moratuwa
    Sri Lanka

    ReplyDelete

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