Categories
Intermediate

La Sagrada Familia

Two congruent right triangles on a common baseline have an overlap of variable size. What is the proportion of the minimal area to the maximal area?

Categories
Advanced

The sneak peek

A rectangle with given side lengths is folded back and forth such that the corner touches the opposite side as shown. What is the minimal shaded fraction?

Categories
Intermediate

The balancing act

A square with two perpendicular lines. What is the minimal blue fraction?

Categories
Advanced

The ocean sunset

A semicircle is inscribed in a rectangle. What is the minimal covered fraction?

Categories
Advanced

The lemon slice

A semicircle is inscribed in a quarter circle. What is the minimal yellow fraction?

Categories
Advanced

The Common Snowdrop

A square contains a smaller square. Their vertices are cyclically connected as shown, forming four triangles. What is the minimal green area fraction?

Categories
Intermediate

The magic mirror

You are standing in front of a mirror. Your shoulder width is 50 cm and your eyes are 6 cm apart. What is the minimum mirror width for a stereo view of yourself?

Categories
Advanced

Who’s afraid of red, yellow and blue?

Three squares. The top line segment is variable in length. What’s the minimal blue fraction?

Categories
Advanced

The party hat

A cone has height 6 and base diameter 6. On it lie two points, one exactly halfway up, the other diametrically opposed at the base. What’s the shortest distance between these points going along the cone surface?

Categories
Advanced

The lazy spider

A spider situated at point A on the outside of a cylinder with diameter 4 and height 3 is trying to get to a fly at point C on the complete opposite side as fast as possible. What is the shortest route?