3rd Grade Math 11.3, Algebra, Find Unknown Side Lengths

We can find the unknown length of a side in a plane shape when we know its perimeter. We add the given side lengths and subtract there sum from the given perimeter. The perimeter of a figure is the distance around all the sides of the figure. When we add the given side lengths, we can use a variable to take the place of the unknown length. We find unknown side lengths for a rectangle, square, regular hexagon, and irregular shaped polygons.

3rd Grade Math 11.1, Model Perimeter


3rd Grade Math 11.2, Find and Measure Perimeter


3rd Grade Math Playlist (2015)


I'm using the Houghton Mifflin Go Math!
2015 copyright textbook for this playlist.

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