Perimeter

Perimeter is the distance around the outside of a shape. It is the total length of all the sides of a shape. To find the perimeter of a shape, you simply add up the lengths of all its sides.

Formulas for Perimeter

Here are the formulas for finding the perimeter of some common shapes:

• Rectangle: Perimeter = 2 * (length + width)
• Square: Perimeter = 4 * side length
• Triangle: Perimeter = sum of all three sides
• Circle: Perimeter = 2 * π * radius (or π * diameter)

Example Problems

Let's work through a couple of example problems to practice finding the perimeter of different shapes:

1. Rectangle: If the length of a rectangle is 5 cm and the width is 3 cm, what is the perimeter?

   Perimeter = 2 * (5 + 3) = 2 * 8 = 16 cm

2. Square: If a square has a side length of 6 cm, what is the perimeter?

   Perimeter = 4 * 6 = 24 cm

3. Triangle: If the sides of a triangle are 4 cm, 7 cm, and 9 cm, what is the perimeter?

   Perimeter = 4 + 7 + 9 = 20 cm

4. Circle: If a circle has a radius of 5 cm, what is the perimeter?

   Perimeter = 2 * π * 5 = 10π cm (or approximately 31.42 cm if using 3.14 for π)

Study Tips

Here are some tips for studying and mastering the concept of perimeter:

• Practice calculating the perimeter of different shapes, such as rectangles, squares, triangles, and circles, using the appropriate formulas.
• Use grid paper to draw shapes and then calculate their perimeters to visualize the concept.
• Work through word problems that involve finding the perimeter of real-life objects or scenarios.
• Review the formulas regularly to ensure you remember how to find the perimeter of each type of shape.

With regular practice and understanding of the formulas, you'll become a pro at finding the perimeter of any shape!