Loading the lesson
Loading the lesson
Search AllRounder.ai
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Learn it your way
A short class with Sarah and her students. The other ways are under More.
Sign up free to listen. Transcripts are free to read.
Let's start with the square. Who can tell me what the perimeter of a square is?
Isn't it just four times the length of one side?
Absolutely correct! So, if the side is 5 cm, what would the perimeter be?
That would be 4 times 5, which is 20 cm!
Exactly! Remember the formula: P = 4 × side. A way to remember it is 'Fourly Square' since all sides are equal.
Now, let's move on to rectangles. What is the formula for calculating the perimeter of a rectangle?
Is it 2 times the length plus width?
Very close! The complete formula is P = 2(l + w). Can anyone give me an example using this?
If the length is 8 cm and the width is 4 cm, then the perimeter would be 2 times (8 + 4), which is 24 cm!
Great job! To make it easier to remember, you can think of 'Lengthy Width Sum' since you're adding both dimensions.
Finally, let's discuss circles. Who can share the formula for the circumference?
That would be 2πr, where r is the radius, right?
Correct! Now, if the radius is 7 cm, what would the circumference be?
Using 3.14 for π, it would be 2 × 3.14 × 7, which is approximately 43.96 cm!
Exactly! You can use the phrase 'Circle's Radius Double π' to help remember that formula.
For the square, just multiply by four, a simple math you can't ignore.
Imagine a square in a garden, each side equally nice. To find its perimeter, gather the sides, multiply by four—simple and precise!
For rectangles, remember L and W, add them up and double too; it's P equals two times L plus W!
C for Circle, 2 for two π, R for radius—it's simple as pie!
Term
Perimeter of a square formula
Click to flip
Term
Perimeter of a rectangle formula
Click to flip
Term
Circumference formula
Click to flip
The total distance around a two-dimensional shape.
The perimeter of a circle.
The distance from the center of a circle to any point on its circumference.
A line segment that forms part of the boundary of a geometric shape.
The longer dimension of a rectangle.
The shorter dimension of a rectangle.
This section presents key formulas for calculating the perimeter of various two-dimensional shapes, including squares, rectangles, and circles.
In this section, students will learn how to calculate the perimeter of common 2D shapes such as squares, rectangles, and circles. Understanding these formulas is essential for solving problems related to measurement in geometrical contexts.
This section focuses on the perimeter formulas for two-dimensional shapes, which are vital for calculating the outer boundaries of geometric figures. We will cover the following key shapes:
Square: The formula for the perimeter of a square is given by 4 times the length of one side (P = 4 × side). This formula highlights that all four sides of a square are equal.
Rectangle: The perimeter of a rectangle can be calculated using the formula P = 2(l + w), where l is the length and w is the width. This indicates that the perimeter is the sum of all sides comprising the rectangle.
Circle (Circumference): The perimeter of a circle, known as the circumference, is calculated using the formula C = 2πr, where r is the radius of the circle. This formula reflects the relationship between radius and the total distance around the circle.
Understanding these formulas allows students to engage in various real-world applications, positioning them for success as they apply these concepts in different contexts throughout the chapter on mensuration.