Lesson · Grade 3 · Mathematics
Perimeter: the distance around a shape
- Grade 3
- Mathematics
- 59 s
- British Columbia
- BC3-MA-24
An ant walks once around a 6 cm by 3 cm rectangle, which shows that the perimeter is the distance all the way around. The sides are measured and added one at a time as the ant walks each side again (6 + 3 = 9, 9 + 6 = 15, 15 + 3 = 18), giving 18 cm; then a circle shows that the distance around it is called its circumference, as an idea only with no formula.
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In one sentence
The question this lesson answers
How far is it all the way around this rectangle?
An ant walks once around the edge, back to where it started.
Transcript
What the lesson says
How far is it all the way around this rectangle?
An ant walks once around the edge, back to where it started.
The distance around a shape is called its perimeter.
We measure each side: 6, 3, 6 and 3 centimetres.
Now add the four side lengths together.
6 plus 3 is 9.
9 plus 6 is 15.
15 plus 3 is 18.
So the perimeter of this rectangle is 18 centimetres.
A circle has no straight sides.
The distance around a circle is called its circumference.
Perimeter is the distance around, so add up all the side lengths.
Curriculum
Where this fits
- British Columbia, Grade 3
Mathematics, Geometry and measurement: measurement, using standard units (linear, mass, and capacity)BC3-MA-24
Previous: Millilitres and Litres: Filling a 1 Litre JugNext: Area: How Many Squares Cover a Shape
- British Columbia, Grade 4
Mathematics, Geometry and measurement: perimeter of regular and irregular shapesBC4-MA-24
Previous: Regular and Irregular PolygonsNext: Line Symmetry: Folding a Shape Onto Itself
This lesson is also listed in Grade 4.
The outcomes and strands follow the British Columbia curriculum.
Keep going
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1 min 21 sArea and Perimeter: What Is the Difference?
Grade 5 · 1 min 21 s
1 min 5 sArea of a Circle from the Radius or the Diameter
Grade 7 · 1 min 5 s
1 min 14 sArea of a Parallelogram: Cut and Slide into a Rectangle
Grade 6 · 1 min 14 s
1 min 18 sArea of a Rectangle: Count the Squares, Then Multiply
Grade 5 · 1 min 18 s
1 min 16 sArea of a Trapezoid: Two Copies Make a Parallelogram
Grade 6 · 1 min 16 s
1 min 19 sArea of a Triangle: Half of a Parallelogram
Grade 6 · 1 min 19 s
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