IXL | Perimeter: find the missing side length

The perimeter of the triangle is

units

What is the length of the missing side?

units

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Learn with an example

question

The perimeter of the shape is

units

What is the length of the missing side?

units

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

units

The length of one side is missing.

units

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

units

Add the lengths of the sides you know.

Find the side length that makes the addition sentence true.

The missing side length is

units

Looking for more? Try these:

Lesson: Perimeter

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Teacher tools

Work it out

Not feeling ready yet? These can help:

PP.6Perimeter: find the missing side length

HH.1Perimeter of polygons

Lesson: Perimeter

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