CK-12 Foundation
Ck 12: Interactive Geometry: 1.3 Polygons
Explore the structure and measurement of polygons.
Mathigon
Mathigon: Algebra: Figurate Numbers
There are many other sequences that are based on certain geometric shapes. These sequences are often called Figurate numbers, numbers that can be represented using geometric shapes. Examples include square, triangle, and tetrahedral...
CK-12 Foundation
Ck 12: Interactive Geometry: 1.5 Quadrilaterals
Explore and measure a variety of quadrilaterals.