IXL | Perimeter of polygons: find the missing side lengths

The perimeter of the shape is

yards

What is the length of the missing side?

yards

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Learn with an example

question

The perimeter of the shape is

yards

What is the length of the missing side?

yards

key idea

The perimeter of a shape is the distance around the shape. It is the total length of the shape's sides.

solution

The perimeter of the shape is

yards

The length of one side is missing.

To find the missing side length, write an addition sentence for the perimeter of the shape. The perimeter of a shape equals the sum of all of its side lengths.

perimeter

The perimeter is

yards

Add the lengths of the sides you know.

Subtract the lengths of the sides you know from the perimeter.

–

The missing side length is

yards

Looking for more? Try these:

Lesson: Perimeter

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Teacher tools

Work it out

Not feeling ready yet? These can help:

PP.5Perimeter of polygons

P.6Subtract two-digit numbers - with regrouping

N.15Add three numbers up to two digits each

X.7Division facts up to 10

Lesson: Perimeter

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