It's all about the EDGES

Perimeter means you measure all around the edges of something.

A fat "L" shape made of two
rectangles

That's what we did in our hallway. We used meter sticks. Each meter stick is 100 cm long.That's a bit more than 3 inches longer than a yard, by the way!

In class, we learned about measuring perimeter of different rectangles. But, our hallway is not really a rectangle. It is more like a fat "L" shape. 

So, we had to make a choice. We could measure every wall, even behind all the junk piled down past the Shop Room. Then, we would add all those "edges" up.

Measuring the long wall

Or, we could figure out the lengths of some walls without measuring them. We can do this because a rectangle has opposite sides the exact same length. And, we can "chop" the L shape into two rectangles.

We used our hallway measurements and the diagram above. We added up all the sides to get the perimeter.

We figured out that the perimeter of our hallway is 97 whole meters and 216 centimeters.

Then, we figured out that 216 centimeters is actually 2 meters and 16 centimeters.

So, our total perimeter = 99 m 16 cm.

Our next project is going to use both perimeter (measure edges around) and area (measure square units that fill a shape.) 

We are pretending we were hired as building contractors to create a K-5 playground. We have a budget of $25,000 to build it. But, the costs are very expensive for some things. So, come back and read next week to see what we decide to do!