The gremlin

Two circles and three coloured isosceles triangles. Prove that the circles are concentric.

Scroll down for a solution to this problem.


The center of the large circle is the intersection of the perpendicular bisectors of the three triangles, and the center of the small circle is the intersection of the bisectors. Since they are isosceles, they are the same point.

This solution was provided by Ignacio Larrosa Cañestro.


The gremlin
Evil little creature
Little elf with supernatural powers
He does not like the light neither the water
Neither the sun
Or food after midnight
The mogwai turned gremlin
By the magic
Of metamorphosis
Imaginary creature
He is a part of the mystery
In the horror movie


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