Solved Examples: Classifying Polygons by Sides, Vertices, and Type

📚 Quick Study Guide

• 🔢 A polygon is a closed, two-dimensional shape with straight sides.
• 📐 The name of a polygon is determined by the number of its sides and angles.
• 👁️‍🗨️ Vertices are the points where the sides of a polygon meet. The number of vertices always equals the number of sides.
• 🔗 Here's a quick reference:
  • ♦️ Triangle: 3 sides, 3 vertices
  • ⏹️ Quadrilateral: 4 sides, 4 vertices
  • ⬣ Pentagon: 5 sides, 5 vertices
  • ⬡ Hexagon: 6 sides, 6 vertices
  • ⬢ Heptagon: 7 sides, 7 vertices
  • オク Octagon: 8 sides, 8 vertices
  • ⧙ Nonagon: 9 sides, 9 vertices
  • ⬟ Decagon: 10 sides, 10 vertices
• 💡 Polygons can be regular (all sides and angles equal) or irregular (sides and angles not all equal).
• 📝 Concave polygons have at least one interior angle greater than 180 degrees. Convex polygons have all interior angles less than 180 degrees.

✍️ Practice Quiz

1. What type of polygon has 5 sides?
   1. A. Quadrilateral
   2. B. Pentagon
   3. C. Hexagon
   4. D. Triangle
2. A polygon has 8 vertices. What is its name?
   1. A. Heptagon
   2. B. Hexagon
   3. C. Octagon
   4. D. Nonagon
3. Which of the following is NOT a quadrilateral?
   1. A. Square
   2. B. Rectangle
   3. C. Triangle
   4. D. Parallelogram
4. How many sides does a decagon have?
   1. A. 6
   2. B. 8
   3. C. 10
   4. D. 12
5. What distinguishes a regular polygon from an irregular polygon?
   1. A. Regular polygons are always larger.
   2. B. Regular polygons have equal sides and angles.
   3. C. Irregular polygons have more sides.
   4. D. Regular polygons are always concave.
6. A polygon has 7 sides. What is it called?
   1. A. Hexagon
   2. B. Heptagon
   3. C. Octagon
   4. D. Pentagon
7. Which of the following polygons could be concave?
   1. A. Equilateral Triangle
   2. B. Square
   3. C. Pentagon
   4. D. Heptagon