AlgèbreFacile
Math Learning PlatformPerimeters and Areas - Simple Shapes
📖 About this lesson
Calculate perimeters and areas of basic geometric shapes
Perimeters and Areas
Perimeter
The perimeter is the ,[object Object], of a shape.
Rectangle
[object Object]
📝 Example
Example: L=5cm, w=3cm P = 2 × (5+3) = 16 cm
Square
[object Object]
📝 Example
Example: side=4cm P = 4 × 4 = 16 cm
Triangle
[object Object]
📝 Example
Example: 3cm, 4cm, 5cm P = 3 + 4 + 5 = 12 cm
Circle (Circumference)
[object Object], or ,[object Object]
π ≈ 3.14
📝 Example
Example: radius=2cm P = 2 × 3.14 × 2 = 12.56 cm
Area
Area is the ,[object Object], of a shape (in units²).
Rectangle
[object Object]
📝 Example
Example: L=5cm, w=3cm A = 5 × 3 = 15 cm²
Square
[object Object]
📝 Example
Example: side=4cm A = 4² = 16 cm²
Triangle
[object Object]
📝 Example
Example: base=6cm, height=4cm A = (6 × 4) / 2 = 12 cm²
Circle
[object Object]
📝 Example
Example: radius=3cm A = 3.14 × 3² = 28.26 cm²
Unit conversions
Length
1 m = 100 cm = 1000 mm 1 km = 1000 m
Area
1 m² = 10,000 cm² 1 cm² = 100 mm²
Example 1
Calculer le périmètre d'un rectangle de 8m sur 5m
26 m
P = 2 × (8 + 5) = 2 × 13 = 26 m
Example 2
Calculer l'aire d'un triangle de base 10cm et hauteur 6cm
30 cm²
A = (10 × 6) / 2 = 30 cm²
Example 3
Un carré a un périmètre de 20cm. Quelle est son aire ?
25 cm²
Côté = 204 = 5cm. Aire = 5² = 25 cm²
Ready to Practice? 💪
5 exercise(s) available for this lesson
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