Lesson: This lesson has students explore areas of rectangular and irregular shapes on a grid to help them understand the concept of area and the units in which area is measured.

Lesson: Helps students understand there are a variety of ways to solve problems. This lesson also gives students practice in using various methods to find the areas of irregular shapes.

Lesson: This lesson shows elementary students how they can know, for certain, that rigid motions like reflections, rotations, and translations create a shape congruent to the original.

Activity: Learn the relationship between perimeter and area. A shape will be automatically generated with the perimeter that you choose. Calculate the area of this shape. Area Explorer is one of the Interactivate assessment explorers.

Activity: Visualize factors through building rectangular areas on a grid. First enter all the factorizations of a number, then draw each factor set as an area on the grid. Factorize is one of the Interactivate assessment explorers.

Activity: Visualize factors through building rectangular areas on a grid. As you draw each factor set on the grid, the factors will be listed. Factorize 2 is one of the Interactivate assessment explorers.

Activity: Build a "floor tile" by dragging the corners of a quadrilateral. Learn about tessellation of quadrilateral figures when the shape you built is tiled over an area.

Activity: Learn the relationship between perimeter and area. A shape will be automatically generated with the area that you choose. Calculate the perimeter of this shape. Perimeter Explorer is one of the Interactivate assessment explorers.

Activity: This activity operates in one of two modes: auto draw and create shape mode, allowing you to explore relationships between area and perimeter. Shape Builder is one of the Interactivate assessment explorers.

Activity: Learn the relationship between perimeter and area. A random shape will be automatically generated. Calculate the area and perimeter of this shape. Shape Explorer is one of the Interactivate assessment explorers.

Activity: Create a tessellation by deforming a triangle, rectangle or hexagon to form a polygon that tiles the plane. Corners of the polygons may be dragged, and corresponding edges of the polygons may be dragged. Parameters: Colors, starting polygon.