Rectangle
A rectangle is a four-sided polygon with opposite sides that are equal in length and four right angles. The opposite sides of a rectangle are parallel and the adjacent sides are perpendicular to each other.
The formula for the perimeter of a rectangle is: P = 2 * (length + width)
The formula for the area of a rectangle is: A = length * width
Rectangles are commonly found in everyday objects such as doors, windows, and paper.
[Rectangle] Related Worksheets and Study Guides:
.◂Math Worksheets and Study Guides First Grade. Shapes
Study Guide
Shapes 
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Tangram Animals Activity Lesson
A Shape Picture Worksheet/Answer key
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Space Worksheet/Answer key
Shapes Worksheet/Answer key
Shapes Worksheet/Answer key
2D Space Worksheet/Answer key
2D Space Worksheet/Answer key
2D Space Worksheet/Answer key
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Shapes
Activity LessonActivity LessonWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyVocabulary/Answer keyVocabulary/Answer keyThe resources above cover the following skills:
Algebra (NCTM)
Understand patterns, relations, and functions.
Sort, classify, and order objects by size, number, and other properties.
Geometry (NCTM)
Analyze characteristics and properties of two- and three-dimensional geometric shapes and develop mathematical arguments about geometric relationships.
Recognize, name, build, draw, compare, and sort two- and three-dimensional shapes.
Describe attributes and parts of two- and three-dimensional shapes.
Use visualization, spatial reasoning, and geometric modeling to solve problems.
Recognize geometric shapes and structures in the environment and specify their location.