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Each side of a regular polygon measures 9 cm and its perimeter is 45 cm. Which polygon is it?

Class 6MensurationMensuration
  • ASquare
  • BPentagon
  • CHexagon
  • DOctagon

Step-by-Step Solution

Number of sides = perimeter ÷ side length = 45 ÷ 9 = 5, and a regular polygon with 5 sides is a pentagon. A square would need only cm of boundary and a hexagon would need cm.
Answer: B) Pentagon

Key idea: Perimeter shortcuts for special shapes

**Rectangle**: opposite sides are equal, so perimeter = l + b + l + b = 2(l + b).

**Square**: all four sides equal, so perimeter = 4 × s.

**Equilateral triangle**: all three sides equal, perimeter = 3 × s.

**Regular polygon with n sides of length s**: perimeter = n × s.

These shortcuts are just 'add the sides' written shorter.

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