🌟 Miss Brenda's Grade 4 Math Class 🌟

📏 What is Perimeter?

Perimeter = the sum of all the sides of a shape.

We usually measure perimeter in centimetres (cm) or metres (m).

⬛ Perimeter of a Rectangle

The easiest way: Add all four sides OR use the formula:

Perimeter = 2 × (length + width)

Example: Rectangle 6 cm long and 4 cm wide

P = 2 × (6 + 4) = 2 × 10 = 20 cm

Or: 6 + 4 + 6 + 4 = 20 cm

⬛ Perimeter of a Square

All sides are equal, so:

Perimeter = 4 × side

Example: Square with sides of 5 cm

P = 4 × 5 = 20 cm

⭐ Perimeter of Irregular Shapes

Just add up all the outside sides!

Example:
Sides: 8 cm, 3 cm, 5 cm, 6 cm, 4 cm

Perimeter = 8 + 3 + 5 + 6 + 4 = 26 cm

✏️ Let’s Practice Together, My Dear Student!

Practice 1: Rectangles

1. Length 9 cm, width 4 cm → 26 cm
2. Length 12 cm, width 7 cm → 38 cm

Practice 2: Squares

1. Side = 8 cm → 32 cm
2. Side = 15 cm → 60 cm

Practice 3: Irregular Shapes & Word Problems

1. A playground has sides: 25 m, 18 m, 25 m, 18 m. What is the perimeter?
86 metres

2. You want to put a fence around a garden that is 12 m long and 8 m wide. How much fencing do you need?
40 metres

Challenge Question

A shape has sides of 6 cm, 9 cm, 4 cm, 5 cm, and 7 cm. What is the perimeter?
31 cm

Fantastic Job, My Dear Student! 🎉

You now understand perimeter very well! You can find the perimeter of rectangles, squares, and irregular shapes.

I am so proud of you. Next time you see a picture frame, a garden, or a soccer field, try to think about its perimeter!

💕 You are smart. You are kind. You can do hard things.