Perimeter and area are two ways to measure 2D shapes.
Perimeter is the total distance around a shape.
Area is the amount of space inside a shape.
Let's review how to find the area and perimeter.
To find the perimeter, add up the lengths of all the sides.
Let's say we have a triangle.
Its sides are a, b, and c long.
To find the perimeter, we just add up the length of all its sides.
a + b + c = perimeter
Can you find the perimeter of this triangle?
You just add the length of all the sides.
7 + 8 + 9 = 24
The perimeter of this triangle is 24.
Remember: If the sides have a unit of measure, make sure to write the perimeter with the same unit of measure.
So if the side lengths were measured in inches, we write the perimeter in inches.
7 in + 8 in + 9 in = 24 inches
If the sides were in meters, then we write meters after 24.
7 m + 8 m + 9 m = 24 meters
Great work learning about perimeter.
When finding the area of a shape, we try to figure out how much space it covers.
There are different formulas for each type of shape.
For the area of a rectangle, we multiply its width and its height.
Let's write the formula:
w × h = area
Let's find the area of this rectangle together.
We multiply its width and height.
9 × 6 = 54
If the unit of measurement for the height and width is meter, then our answer will be 54 square meters.
9 m × 6 m = 54 square meters
If the measurements were in inches, then it would be 54 square inches.
9 in × 6 in = 54 square inches
We add the word "square" because we measure area in square units, a 2D unit.
It's like counting how many squares can fit inside a shape's space.
Fantastic learning about areas. 👏
Now, complete the practice. It'll help you remember what you learned for longer.