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8.03 Other problems with perimeter

Lesson

Are you ready?

Do you remember how to find the perimeter of a rectangle? Let's try this problem to practice.

Find the perimeter of the rectangle shown.

Learn

In this video, we deconstruct and reconstruct a rectangle. If we know the perimeter and one of the side lengths we can work out the other.

Apply

question 1

Find the missing side length of the rectangle shown.

 

Learn

If we know the perimeter of a square, we can find the side length by dividing the perimeter by $4$4. This works because a square has $4$4 equal sides.

Apply

Question 2

Find the side length of the square shown.

 

Remember!

We can find the perimeters of rectangles and squares by either using a formula or finding the sum of their side lengths.

Outcomes

4.MD.A.3

Know and apply the area and perimeter formulas for rectangles in real world and mathematical contexts. For example, find the width of a rectangular room given the area of the flooring and the length, by viewing the area formula as a multiplication equation with an unknown factor.

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