Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a man walking.

Man Walking

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a man walking.

Man Walking

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a man wearing a tuxedo.

Man Wearing a Tuxedo

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a man wearing a tuxedo.

Man Wearing a Tuxedo

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a man wearing a tuxedo.

Man Wearing a Tuxedo

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a man wearing a tuxedo.

Man Wearing a Tuxedo

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a medium house.

Medium House

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a medium house.

Medium House

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a medium house.

Medium House

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a medium house.

Medium House

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mocking bird.

Mocking Bird

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mocking bird.

Mocking Bird

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mocking bird.

Mocking Bird

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mocking bird.

Mocking Bird

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mountain.

Mountain

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mountain.

Mountain

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mountain.

Mountain

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a mountain.

Mountain

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Illustration of a circle inscribed in a regular nonagon. This could also be described as a regular nonagon circumscribed about a circle.

Circle Inscribed in a Nonagon

Illustration of a circle inscribed in a regular nonagon. This could also be described as a regular nonagon…

Regular nonagon inscribed in a circle.

Nonagon Inscribed in a Circle

Regular nonagon inscribed in a circle.

Illustration of an equilateral triangle inscribed in a regular nonagon. This could also be described as a a regular nonagon circumscribed about an equilateral triangle.

Triangle Inscribed in a Nonagon

Illustration of an equilateral triangle inscribed in a regular nonagon. This could also be described…

Illustration of 2 regular concentric nonagons.

2 Concentric Nonagons

Illustration of 2 regular concentric nonagons.

Illustration of 2 regular concentric nonagons.

2 Concentric Nonagons

Illustration of 2 regular concentric nonagons.

Illustration of 3 regular concentric nonagons that are equally spaced.

3 Concentric Nonagons

Illustration of 3 regular concentric nonagons that are equally spaced.

Illustration of 4 regular concentric nonagons that are equally spaced.

4 Concentric Nonagons

Illustration of 4 regular concentric nonagons that are equally spaced.

"A polygon of...eight sides [is] an octagon." —Hallock 1905

Octagon

"A polygon of...eight sides [is] an octagon." —Hallock 1905

Illustration of a regular octagon circumscribed about a square. This could also be described as a square inscribed in a regular octagon.

Octagon Circumscribed About a Square

Illustration of a regular octagon circumscribed about a square. This could also be described as a square…

Illustration of a concave equilateral octagon.

Concave Equilateral Octagon

Illustration of a concave equilateral octagon.

Illustration of an irregular concave octagon. This polygon has some symmetry.

Irregular Concave Octagon

Illustration of an irregular concave octagon. This polygon has some symmetry.

Illustration of an irregular concave octagon.

Irregular Concave Octagon

Illustration of an irregular concave octagon.

Illustration of an irregular concave octagon. This polygon has some symmetry.

Irregular Concave Octagon

Illustration of an irregular concave octagon. This polygon has some symmetry.

Illustration of an irregular concave octagon. This polygon has some symmetry.

Irregular Concave Octagon

Illustration of an irregular concave octagon. This polygon has some symmetry.

Illustration of an irregular convex octagon. This polygon has some symmetry.

Irregular Convex Octagon

Illustration of an irregular convex octagon. This polygon has some symmetry.

Illustration of an irregular convex octagon. This polygon has some symmetry.

Irregular Convex Octagon

Illustration of an irregular convex octagon. This polygon has some symmetry.

Illustration of an irregular convex octagon.

Irregular Convex Octagon

Illustration of an irregular convex octagon.

Illustration of an irregular convex octagon. This polygon has some symmetry.

Irregular Convex Octagon

Illustration of an irregular convex octagon. This polygon has some symmetry.

Illustration of an irregular convex octagon. This polygon has some symmetry.

Irregular Convex Octagon

Illustration of an irregular convex octagon. This polygon has some symmetry.

Illustration of an octagon with symmetry with respect to two axes perpendicular to each other. It is symmetrical with respect to their intersection as a center.

Octagon with Symmetry

Illustration of an octagon with symmetry with respect to two axes perpendicular to each other. It is…

Illustration of 2 regular concentric octagons.

2 Concentric Octagons

Illustration of 2 regular concentric octagons.

Illustration of 2 regular concentric octagons.

2 Concentric Octagons

Illustration of 2 regular concentric octagons.

Illustration of 3 regular concentric octagons that are equally spaced.

3 Concentric Octagons

Illustration of 3 regular concentric octagons that are equally spaced.

Illustration of 4 regular concentric octagons that are equally spaced.

4 Concentric Octagons

Illustration of 4 regular concentric octagons that are equally spaced.

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a palm tree.

Palm Tree

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a palm tree.

Palm Tree

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a palm tree.

Palm Tree

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a palm tree.

Palm Tree

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Parallelogram with angles labeled.

Parallelogram

Parallelogram with angles labeled.

Illustration of a parallelogram, a quadrilateral which has opposite sides parallel.

Parallelogram

Illustration of a parallelogram, a quadrilateral which has opposite sides parallel.

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parallelogram.

Parallelogram

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parallelogram.

Parallelogram

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parallelogram.

Parallelogram

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parallelogram.

Parallelogram

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Illustration of a parallelogram with altitude and diagonal drawn.

Altitude and Diagonal of a Parallelogram

Illustration of a parallelogram with altitude and diagonal drawn.

Illustration of a how to construct a square equivalent to a given parallelogram.

Parallelogram Used to Construct Equivalent Square

Illustration of a how to construct a square equivalent to a given parallelogram.

Illustration of a parallelogram with diagonals drawn to show they bisect each other.

Parallelogram With Diagonals Bisecting Each Other

Illustration of a parallelogram with diagonals drawn to show they bisect each other.

Illustration used to prove the theorem "Two parallelograms are equal if two sides and the included angle of one are equal respectively to two sides and the included angle of the other."

2 Equal Parallelograms

Illustration used to prove the theorem "Two parallelograms are equal if two sides and the included angle…

Illustration of a two equal parallelograms. Two parallelograms are equal, if two sides and the included angle of the one are equal, respectively, to two sides and the included angle of the other.

Equal Parallelograms

Illustration of a two equal parallelograms. Two parallelograms are equal, if two sides and the included…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parrot fish.

Parrot Fish

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parrot fish.

Parrot Fish

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures consisting of triangles, squares, and parallelograms are used to construct the given shape. This tangram depicts a parrot fish.

Parrot Fish

Tangrams, invented by the Chinese, are used to develop geometric thinking and spatial sense. Seven figures…