Polygon
A polygon is a two-dimensional shape that is formed by straight lines. These straight lines are called the sides of the polygon, and they meet at points called vertices. A polygon must have at least three sides and three vertices.
There are different types of polygons based on the number of sides they have:
- Triangle: A polygon with three sides.
- Quadrilateral: A polygon with four sides. Examples include squares, rectangles, parallelograms, and rhombuses.
- Pentagon: A polygon with five sides.
- Hexagon: A polygon with six sides.
- Heptagon: A polygon with seven sides.
- Octagon: A polygon with eight sides.
- and so on...
Polygons can also be classified as regular or irregular:
- Regular Polygon: A polygon with all sides of equal length and all angles of equal measure.
- Irregular Polygon: A polygon with sides and/or angles of different lengths and measures.
It's important to note that the sum of the interior angles of a polygon with n sides can be found using the formula: (n-2) * 180 degrees.
[Polygon] Related Worksheets and Study Guides:
.◂Math Worksheets and Study Guides Third Grade. Expanding Numbers
Study Guide
Expanding Numbers 
Worksheet/Answer key
Expanding Numbers Worksheet/Answer key
Expanding Numbers Worksheet/Answer key
Expanding Numbers
Worksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyThe resources above cover the following skills:
Number and Operations (NCTM)
Understand numbers, ways of representing numbers, relationships among numbers, and number systems.
Understand the place-value structure of the base-ten number system and be able to represent and compare whole numbers and decimals.
Recognize equivalent representations for the same number and generate them by decomposing and composing numbers.
Algebra (NCTM)
Use mathematical models to represent and understand quantitative relationships.
Model problem situations with objects and use representations such as graphs, tables, and equations to draw conclusions.
Connections to the Grade 3 Focal Points (NCTM)
Number and Operations: Building on their work in grade 2, students extend their understanding of place value to numbers up to 10,000 in various contexts. Students also apply this understanding to the task of representing numbers in different equivalent forms (e.g., expanded notation). They develop their understanding of numbers by building their facility with mental computation (addition and subtraction in special cases, such as 2,500 + 6,000 and 9,000 - 5,000), by using computational estimation, and by performing paper-and-pencil computations.