A circle divided into six congruent sectors. A smaller concentric circle of radius one quarter of the large one. What fraction is black?
Author: Rik D. Tangerman
The water container
Five congruent squares each of area 14 support a larger square. What area is shaded?
The pulley problem
Two pulleys carrying three weights of 30, 70 and 50 grams. Given that the constellation is in equilibrium, what’s the angle?
The complicated jet
Two congruent squares inside a circle. The extended diagonals meet at the circle circumference. What’s their angle?
The bird’s-eye tipi
A regular hexagon with triangles to an internal point. What fraction is shaded?
The drop shadow
Two congruent squares share a vertex. What’s the angle α?
The distant Alp
A rectangle containing five triangles. What fraction is brown?
The white flags
Three congruent squares and three shared vertices. What fraction is blue?
The divided diagonal
A square diagonal is divided in three by a 45-degree angle. Two pieces are given, what is the length of the third?
The dark side
A quarter circle containing two touching semicircles cut by a chord. What fraction is brown?