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Perimeter and Area – Class 6 Mathematics notes, important questions and MCQs
NCERT Class 6 Mathematics, chapter 6. Notes, key terms, important questions with answers and MCQs.
Chapter overview
Perimeter is the distance around a shape; area is the surface it covers. Rectangles and squares have simple formulas.
Perimeter
- Perimeter = sum of all sides.
- Rectangle: 2(l + b); square: 4 × side; equilateral triangle: 3 × side.
- Units: cm, m.
Area
- Area = number of unit squares covering the shape.
- Rectangle: l × b; square: side × side.
- Units: cm², m². Shapes with the same perimeter can have different areas.
Key terms
- Perimeter
- total length of the boundary
- Area
- amount of surface enclosed
- Square unit
- unit of area, the area of a square of side 1 unit (cm², m²)
Formulas
- Rectangle: P = 2(l + b), A = l × b
- Square: P = 4a, A = a²
Important questions with answers
Find the perimeter of an equilateral triangle of side 7 cm.2 marks
Perimeter = 3 × 7 = 21 cm.
A rectangular room is 6 m long and 4 m wide. Find the cost of tiling the floor at ₹150 per m².3 marks
Area = 6 × 4 = 24 m². Cost = 24 × 150 = ₹3,600.
A rectangular park is 50 m long and 30 m wide. A 2 m wide path runs inside along its edges. Find the area of the path and the cost of laying it at ₹40 per m².5 marks
Area of park = 50 × 30 = 1,500 m². Inner rectangle = (50 − 4) × (30 − 4) = 46 × 26 = 1,196 m². Path area = 1,500 − 1,196 = 304 m². Cost = 304 × 40 = ₹12,160.
Quick revision
- Perimeter in cm; area in cm².
- Square: P = 4a.
- Same perimeter ≠ same area.
Exam tips
- Fencing needs perimeter; tiling or painting needs area.
- Count half squares as ½ when finding area on squared paper.
Practice MCQs
Perimeter of a square of side 5 cm is
- 10 cm
- 15 cm
- 25 cm
- 20 cm
Show answer
Answer: (d) 20 cm. 4 × 5.
Area of a rectangle 6 cm by 4 cm is
- 10 cm²
- 20 cm²
- 24 cm²
- 48 cm²
Show answer
Answer: (c) 24 cm². 6 × 4.
Perimeter of a rectangle 8 m by 3 m is
- 11 m
- 22 m
- 24 m
- 16 m
Show answer
Answer: (b) 22 m. 2(8 + 3).
The side of a square with perimeter 36 cm is
- 6 cm
- 9 cm
- 12 cm
- 18 cm
Show answer
Answer: (b) 9 cm. 36 ÷ 4.
A square has perimeter 36 cm. Its area is
- 36 cm²
- 144 cm²
- 9 cm²
- 81 cm²
Show answer
Answer: (d) 81 cm². Side 9 cm.
How many 2 cm × 2 cm tiles cover a 10 cm × 8 cm board?
- 80
- 40
- 20
- 16
Show answer
Answer: (c) 20. 80 ÷ 4.
A rectangle 9 cm × 4 cm and a square of side 6 cm have
- equal areas
- equal perimeters
- both equal
- neither equal
Show answer
Answer: (a) equal areas. Both 36 cm²; perimeters 26 and 24.
A rectangle 12 m × 8 m is fenced 3 times around. Wire needed is
- 40 m
- 96 m
- 120 m
- 288 m
Show answer
Answer: (c) 120 m. Perimeter 40 m × 3.
All chapters of Class 6 Mathematics
Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.