Khan Academy: Finding Missing Side When Given Area

Area is the amount of space that takes up the inside of a figure. To find the area of a rectangle, one must multiply the length by the width. Here, third graders are challenged to find the missing side length, given the area.

Perimeter is the total distance around an object. One can find the perimeter of a rectangle or square by adding all four side lengths together. These worksheets require third graders to find the missing side length, given the...

Lindsay finds missing side lengths on polygons when given all other side lengths and the perimeter.

Demonstrates how to use a known perimeter to calculate the missing length of a side of a polygon. [4:54]

Lindsay creates a rectangle with a given area.

Practice finding the area of rectangles by counting unit square. Create rectangles with a given area by covering unit squares. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video...

Find missing factors in 1-digit multiplication problems. Products are less than or equal to 100. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

In this exercise, students find a missing side length when given area of a rectangle. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Lindsay creates a rectangle that has the same area (but different side lengths) than a given rectangle.

Find missing divisors and dividends in 1-digit division problems. Quotients are less than or equal to 10. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video tutorial, or receive hints....