An equilateral triangle containing a parallelogram, another equilateral triangle and a circular arc that is tangent in its base vertices. What is the proportion pink : blue?

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geometry puzzles

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- Post author By Rik D. Tangerman
- Post date June 2, 2022
- 1 Comment on Out of proportion

- Tags area, circle, parallelogram, proportion, triangle

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- Post author By Rik D. Tangerman
- Post date April 29, 2022
- No Comments on Silent circle

A large triangle with one side tangent to a circle. The tangency point is the vertex of a blue parallelogram. What is the red area?

- Tags area, circle, parallelogram, triangle

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- Post author By Rik D. Tangerman
- Post date June 16, 2021
- No Comments on The orange belt

Three squares and three shared vertices. Prove that the orange quadrilateral is in fact a parallelogram.

- Tags parallelogram, quadrilateral, square

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- Post author By Rik D. Tangerman
- Post date May 17, 2021
- No Comments on The skyscraper

A blue parallelogram with an extended diagonal. What is the proportion green : orange?

- Tags area, parallelogram, proportion, triangle

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- Post author By Rik D. Tangerman
- Post date April 1, 2021
- No Comments on The first cut

Using one straight cut, divide this triangle in two pieces. Paste them together to form a parallelogram with perimeter 19.

- Tags cut and paste, parallelogram, triangle

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- Post author By Rik D. Tangerman
- Post date February 2, 2021
- 1 Comment on The balance sheet

A unit square and a parallelogram. What’s the area of the latter?

- Tags area, parallelogram, square

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- Post author By Rik D. Tangerman
- Post date January 4, 2021
- No Comments on The parquet floor

A unit rhombus is surrounded by four congruent parallelograms. All five quadrilaterals have equal area. What are the parallelogram sides x and y?

- Tags area, length, parallelogram, quadrilateral, rhombus

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- Post author By Rik D. Tangerman
- Post date November 25, 2020
- No Comments on Velocipede II

Two circles of area π and 9π respectively are contained in a parallelogram. What’s its area?

- Tags area, circle, parallelogram