Perimeter - the mystery of the unknown side

You're already familiar with perimeter, thanks to a previous lesson. This time we'll look at perimeter examples where one of the sides is missing a number. You'll learn how to create an addition equation to calculate the perimeter, even if one of the sides of the shapes is unknown.  Come with us, as we practice with triangles, rectangles, trapezoids, pentagons, and real world examples!

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3rd

grade

Math

lessons: