Round Robin Tournament

Use the sides and diagonals in a regular polygon to create a round robin tournament.

Diagonals in a Polygon

Consider the number of diagonals in a triangle, quadrilateral, pentagon, hexagon, heptagon, and octagon.

Symmetry Lines II

Find polygons that have line symmetry. Many polygons do not have line symmetry.

Symmetry Lines

Determine the number of symmetry lines a polygon has.

Magic Triangle

Place the digits 1 through 9 in the circles in a very special way.

Counting Triangles

Determine the number of triangles in the diagram.

Non-Overlapping Triangles

Use three lines to form as many triangles as possible.

Lining Up to Find Triangles

Draw lines to find the largest amount of triangles.

Toothpick Transfer

Readjust a diagram to form a number of triangles.

Hidden Triangles

Count the number of triangles in a picture.