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Class 6 Perimeter and Area: cheat sheet
CBSE Mathematics. Perimeter is the distance around a shape; area is the space it covers. Formulas for rectangles, squares and triangles.
Key ideas
- Perimeter is measured in units of length (cm, m); area in square units (cm², m²).
- To find the perimeter of any shape, add the lengths of all its sides.
- Count squares to find area: each full square is 1 square unit; more than half a square counts as one.
- A triangle drawn on the diagonal of a rectangle has half the rectangle’s area.
- Shapes with the same area can have different perimeters, and the other way round.
Remember
| Rectangle | perimeter = 2 × (l + b); area = l × b |
| Square | perimeter = 4 × side; area = side × side |
| Triangle | perimeter = a + b + c; area = ½ × base × height |
| Units | 100 cm = 1 m; 1000 m = 1 km |
Watch out
- Giving area in cm instead of cm².
- Adding only two sides for the perimeter of a rectangle.
- Mixing metres and centimetres in one calculation.
Worked example
Neeraj runs 8 rounds of a square park of side 150 m. How far does he run? Give the answer in km.
Working: one round 4 × 150 = 600 m; 8 rounds = 4800 m = 4.8 km
Answer: 4.8 km
Practise Perimeter and Area
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