In the realm of geometry, the perimeter refers to the total distance around a two-dimensional shape. This can be determined by summing up the lengths of all its sides.
Example: Rectangular Shape
Let's delve into a scenario where a rectangle is depicted on a square grid, with each square equivalent to 1 cm.
To determine the rectangle's perimeter, add the lengths of all sides.
Using the squares, you can ascertain the length of each side:
Sum up all the sides: 7 cm + 7 cm + 4 cm + 4 cm = 22 cm.
An alternative method involves counting the squares around the shape's perimeter.
How do you find the perimeter of a rectilinear shape?
A rectilinear shape has straight sides that intersect at right angles.
You can calculate its perimeter just like any other shape, but with more sides to sum up.
Use the squares to help determine its perimeter, with each square representing 1 cm.
After finding the lengths of each side, add them up:
6 cm + 3 cm + 5 cm + 1 cm + 1 cm + 2 cm
That’s a lot of numbers! To simplify, you can group some numbers together:
6 cm + 3 cm + 5 cm + 1 cm + 1 cm + 2 cm or 9 cm + 6 cm + 3 cm = 18 cm
So, the perimeter of the rectilinear shape is 18 cm.
Example: Work out the missing lengths of this shape to find the perimeter.
Sol:
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1. What is the formula for calculating the perimeter of a shape on a grid? |
2. How do you find the perimeter of a shape on a grid if some sides are missing? |
3. Can the perimeter of a shape on a grid be negative? |
4. How is the concept of perimeter on a grid useful in real-life situations? |
5. Are there any shortcuts or tricks for quickly calculating the perimeter of a shape on a grid? |
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