Categories
Beginner

Parallelism

A trapezium with its diagonals and a parallel line segment. What’s the proportion blue : red?

Categories
Intermediate

Squaring the circle

Two perpendicular squares inside a circle. The circle centre is located on the side of one square. The line segment connecting two vertices has length a. What is the circle area?

Categories
Intermediate

The inner diamond

A triangle with side lengths a and b and an inscribed rhombus. What is the blue fraction in terms of a and b?

Categories
Beginner

The Common Brimstone

A square divided by three line segments. What’s the proportion green : yellow?

Categories
Advanced

Silent circle

A large triangle with one side tangent to a circle. The tangency point is the vertex of a blue parallelogram. What is the red area?

Categories
Intermediate

The yardstick

A rectangle containing a circle and a line segment connecting the top side to the bottom tangency point. What is its area in terms of lengths a and b?

Categories
Intermediate

The Arcus arcade

A semicircle and an inscribed circle. Prove that the circle centre is on the parabola.

Categories
Intermediate

The Suresh similarity

Two squares and a rectangle. Prove that the red triangles are similar.

Categories
Beginner

Tension control

Three squares and a line segment of which a vertex is the midpoint. What is the proportion purple : green?

Categories
Intermediate

A new slant

Two squares and a slanted rectangle share three vertices. What is the total area?