A square and an equilateral triangle are divided in several polygons. What is the proportion yellow : blue?
Month: February 2022
Round and pointy
A circle is inscribed in both a semicircle and a right triangle. The three tangency points are shown. What is the angle α?
The emerging pattern
A square, a circle and its centre. Prove that the six red points are on one circle.
And counting
A triangle containing an altitude and the inscribed circle. One tangency point is shown. The red line segments have equal length. What is the proportion of the triangle sides a : b : c?
The holy number
An equilateral triangle and several line segments. What fraction is purple?
Protection
Two coloured squares inside a triangle inside a square of side length a. What is the length proportion a : b?
Elasticity
Four squares and two triangles. Prove that the two green angles are congruent.
The miniature version
Two rectangles share a vertex. Two line segments connecting opposing vertices and the common side intersect in a single point. Prove that the rectangles are similar.
Wheels in motion
Two tangent circles and a third circle touching the line segment connecting their centres in the tangency point. Prove that the red points (centre and two intersection points) are collinear.
The Transamerica Pyramid
Two squares inscribed in a triangle. What fraction of its area is coloured?