Categories
Beginner

The Swiss cheese

A triangle containing two congruent semicircles. The four tangency points are shown. What fraction is yellow?

Categories
Beginner

Tip of the veil

A square with two right angles. What fraction is yellow?

Categories
Beginner

Pac-Man pack

Four Pac-Men eat the corners of a square while four others stand guard. What fraction of the square is eaten?

Categories
Beginner

Le col bleu

A square with two line segments. What fraction is blue?

Categories
Beginner

Night mountain

A rectangle containing three line segments. What fraction is blue?

Categories
Beginner

Off the grid

A square on a grid containing a red triangle with an extended side. What is the red fraction?

Categories
Advanced

The Cheshire Cat grin

What is the total area of the green teeth relative to the large circle area? (Assume the inner circle radius is 80% of the outer. The 32 lines forming the tooth sides are concurrent, and spaced at equal angles apart.)

Categories
Beginner

All-seeing eye

If the radius shrinks by the factor 1/2 for each smaller circle, what fraction of the whole area is represented by all the blue crescents (separated by the red crescents)? Assume the circles keep going inward forever.

Categories
Intermediate

The beehive

Three regular hexagons, one centre and a triangle. What fraction of the total area is orange?

Categories
Intermediate

The personal letter

Two rectangles share two vertices. What’s the green fraction?