An angle formed by one of the sides of a polygon and extension of its neighboring side.

A polygon in which the sides do not have the same length or the angles do not have the same measure.

The sum of the interior angles of a polygon.

These shapes have the least number of sides and will move freely when built.

These lines stabilize quadrilaterals by turning them into triangles and stopping their shifts.

An angle inside the polygon.

The angle sum of a regular nonagon.

The number of triangles that can be made from a polygon with n sides.

For a quadrilateral to be made, this inequality must be true in the four sides a, b, c, and d, with d as the longest side.

These polygons are often used for construction, due to their inability to shift.

The expression nx180 in a polygon with n sides

The angle sum of a regular decagon.

Congrats! You win a DAILY DOUBLE!!! Here is the answer: The angle sum of a triangle.

These quadrilateral-based instruments are often used in windshield wipers, handcars, and reclining lawn chairs.

The longest side of a triangle.

The exterior angle sum of a triangle

The angle sum of a regular dodecagon.

The polygons that will make splitting polygons into triangles a bit more difficult.(Tia and Cody's Methods)

These are the components of quadrilateral linkages.

With three line segments a, b, and c, and c as the hypotenuse of this imaginary triangle, this must be true for a, b, and c to make a triangle.

The exterior angle sum of any polygon

The angle sum of a regular polygon with n sides.

Congrats! You win a DAILY DOUBLE!!! Here is the answer: The formula for the angle sum of a polygon with n sides using the fact that n triangles can be made from a point inside that polygon and the inside full turn does not belong to that polygon.

Congrats! You win a Daily Double! Here is the answer: This German mathematician devised an interesting principle for quadrilateral linkages in 1883.

3 locations in which triangles are used.