If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

3rd grade

Unit 11: Lesson 2

Perimeter of polygons with missing side lengths

Find a missing side length when given perimeter

Problem

The perimeter of the figure is 31, start text, space, m, end text.
What is the length of the missing side?
start text, m, end text
A four-sided figure with sides labeled as follows: 8 meters 6 meters, question mark meters, and 10 meters.
Stuck?
Stuck?