How many sides does a triangle have?
The correct answer and explanation is:
A triangle has 3 sides.
Explanation (300 words):
A triangle is one of the most fundamental shapes in geometry. The word “triangle” comes from the Latin word triangulus, meaning “three-cornered” or “three-angled.” As the name suggests, a triangle is a polygon — a closed, two-dimensional shape — that has exactly three sides and three angles.
Each side of a triangle is a straight line, and the sides are connected end-to-end to form a closed shape. Where two sides meet is called a vertex (plural: vertices), and the angle formed at each vertex is called an interior angle. The three interior angles in a triangle always add up to 180 degrees.
There are different types of triangles based on their side lengths or angle measures:
- By side length:
- Equilateral triangle: All three sides are equal.
- Isosceles triangle: Two sides are equal.
- Scalene triangle: All three sides are different.
- By angle:
- Acute triangle: All angles are less than 90°.
- Right triangle: One angle is exactly 90°.
- Obtuse triangle: One angle is more than 90°.
The triangle is also the simplest possible polygon. All other polygons — like quadrilaterals (4 sides), pentagons (5 sides), and hexagons (6 sides) — have more than three sides.
Because of its simplicity and stability, the triangle is a critical shape in construction, design, and engineering. For example, triangle-based structures (like trusses) are very strong and commonly used in bridges and buildings because they distribute force evenly.
In summary, a triangle has 3 sides, making it the simplest and one of the most important polygons in both mathematics and real-life applications.