Explanation: In geometry, a polygon is a closed plane figure bounded by straight line segments. The number of sides and angles in a polygon defines its type. A pentagon is a specific type of polygon that has five sides and five angles. The term "pentagon" comes from the Greek words "pente" (five) and "gonia" (angle), which together mean "five angles."
Polygons are classified based on the number of sides they have. For example:
- A triangle has three sides.
- A quadrilateral has four sides.
- A pentagon has five sides.
- A hexagon has six sides.
- A heptagon has seven sides.
- An octagon has eight sides.
Understanding the properties of polygons is crucial in geometry. Each type of polygon has unique characteristics, such as the sum of its interior angles, which can be calculated using the formula \((n-2) \times 180^\circ\), where \(n\) is the number of sides. For a pentagon, the sum of the interior angles is \((5-2) \times 180^\circ = 540^\circ\).
In the context of Indian General Knowledge (GK), understanding basic geometric shapes like the pentagon is important for various competitive examinations. These shapes are often used in questions related to geometry, spatial reasoning, and pattern recognition. For instance, the Pentagon in Washington, D.C., is a famous building named after its shape, which is a regular pentagon.
To summarize, a pentagon is a five-sided polygon, and recognizing this shape is fundamental in geometry and can be tested in various competitive examinations. The correct answer to the question is (A) Pentagon.