Question
The area of a regular polygon with a side of 11 cm is 247.5 cm². If the perpendicular distance from the centre to the side of the polygon is 9 cm, what is the number of sides of the polygon?
This question was previously asked in
RRB NTPC 2025 Under Graduate CBT 1 Question Paper PDF (20-Jun-2026) (Shift 3)
The correct answer is
5
Area of a regular polygon: \(\dfrac12\times\text{perimeter}\times\text{apothem}\).
With side=11 cm, apothem=9 cm, and n sides: \(\dfrac12\times(11n)\times9 = 247.5\).
\(49.5n = 247.5 \Rightarrow n = 5\).
Hence, the polygon has 5 sides.
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