# Lesson 4: Using a Ruler to Measure the Perimeter

Brain Teaser!

Let’s get our brains warmed up! Complete the challenge below, how do you work out the perimeter of a 2D shape? What numbers to you need to add together?

Starter

Yesterday, we looked at how to measure the perimeter of a 2D shape using informal units. Talk to your grown up about how you found it.  Was there anything you found challenging? If your grown up cannot help you, write down what you found difficult and talk to your teacher about it when they call in the week.

Can you remember what is perimeter? How do you calculate the perimeter of a 2D shape?

Today we are going to learn about how to measure the perimeter of 2D shapes using formal methods. What formal methods have we used this week to measure? How do we use a ruler? What number do you start on? Where do you place the ruler?

Work through the PowerPoint below and calculate the perimeter of the 2D shapes using formal units of measure.

Activity

Once you have understood how to calculate the Perimeter of a 2D shape using a ruler we would like you to put it in practice.

Below are different word problem sheets. One star, two star and 3 star; choose the one you feel comfortable with but do challenge yourself!

You must complete at least ONE sheet

Check your answers once you have completed your work with someone at home and go over any that you got incorrect.

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