A semicircle, a square and an isosceles triangle. What’s the angle α?
Category: Advanced
Fun with flags
A triangle with two cevians. What is d/c-b/a?
The Olympic bowl
A parabola is tangent to the equal sides of an isosceles triangle in its equal vertices. Another tangent is drawn as shown. Prove that the red line segments are congruent.
As above, so below
A semicircle, a square, a triangle and two circles. A centre and a tangency point are highlighted. Prove that the circles are congruent.
Mind the gap
A regular hexagon with an equilateral triangle sharing a vertex and having a vertex somewhere along the opposite side. What is the maximum length of line segment g?
The crowded house
Three circles are inscribed in a rectangle. What is the area X in terms of A and B?
The letter box
A rectangle with a diameter and two inscribed squares. What is its area in terms of the square areas A and B?
A close encounter
Two semicircles are tangent to each other’s diameter. Are the line segments connecting their corners parallel?
The extra large
A triangle with a cevian splitting its base in parts of length 2 and 1. What is the angle α?
The stuck boulder
A rectangle contains a circle wedged between two triangles. What is the circle radius in terms of triangle heights a and b?