Finding missing side length when given perimeter | Math | 3rd grade | Khan Academy

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

Practice this yourself on Khan Academy right now: https://www.khanacademy.org/math/cc-third-grade-math/cc-third-grade-measurement/cc-third-grade-perimeter/e/find-a-missing-side-length-when-given-perimeter

Watch the next lesson: https://www.khanacademy.org/math/cc-third-grade-math/cc-third-grade-measurement/cc-third-grade-compare-area-perimeter/v/comparing-area-and-perimeter

Missed the previous lesson? Watch here: https://www.khanacademy.org/math/cc-third-grade-math/cc-third-grade-measurement/cc-third-grade-perimeter/v/perimeter-of-a-shape

3rd grade math on Khan Academy: We know you've been rocking through 2nd grade adding and subtracting all kinds of whole numbers (up to 2 digits, right?). That's awesome! In 3rd grade math we want you to start using bigger numbers and start multiplying and dividing, too. By the way, did you know that some numbers aren’t actually “whole?” They’re “partially whole.” We call them fractions! We want you to start playing around and having fun with those, too. There's also area, perimeter, and place value to be discovered. Whew. We have so much to do and can't wait to do it with you. Let's go!

... https://www.youtube.com/watch?v=_sQ3dqhLsIw Note: All Khan Academy content is available for free at (www.khanacademy.org)