Khan Academy: Finding Perimeter When a Side Length Is Missing

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...

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.

Demonstrates how to find the perimeter of a polygon when a side length is missing. [3:31]

In this exercise, students practice finding perimeter when given side lengths. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly. CCSS.Math.Content.3.MD.D.8 Solve real world and...

Find perimeter of figures when given an image or context. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints. CCSS.Math.Content.3.MD.D.8 Solve real world and...

Calculate the perimeter of a rectangle from its side lengths. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

In this exercise, students practice find the perimeter of shapes by counting unit squares. Students receive immediate feedback and have the opportunity to watch a video tutorial, get hints, and try questions repeatedly.

Lindsay from Khan Academy finds the missing side length on a rectangle when given the area of the rectangle. [3:03]

Find a missing side length for a figure when given the perimeter. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

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