Find the perimeter of a semicircle of diameter 14 cm. (Take π = 227)
- 22 cm
- 36 cm
- 44 cm
- 58 cm
Need a hint?
The perimeter of a semicircle includes the curved arc and the straight diameter. Find the arc length first, then add the diameter.
Worked answer
- Length of the curved part = 12 × π × diameter
- = 12 × 227 × 14
- = 22 cm
- Perimeter = curved part + straight diameter
- = 22 + 14
- = 36 cm
The mistake this question tests
Area and perimeter formulas
Pupils often find only the length of the curved arc (22 cm) and forget to add the straight diameter to get the full perimeter.
How to fix it at home →Wrong answers children often give:
- 22 cm Area and perimeter formulas
- 44 cm Calculation slip
- 58 cm Area and perimeter formulas
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