Year 7 Maths: Identify and Classify Polygons

What is a Polygon?

A polygon is a flat shape with straight sides. The sides must connect to form a closed figure. Think of a polygon like a fence around a garden. If the fence is closed and has straight sides, it’s a polygon!

Key Features of Polygons:

1. Straight Sides: All sides must be straight lines.
2. Closed Shape: The sides must connect to form a complete shape.
3. More than Three Sides: The simplest polygon is a triangle, which has 3 sides.

Types of Polygons

Polygons can be classified based on the number of sides they have. Here are the most common types:

• Triangle: 3 sides
• Quadrilateral: 4 sides
• Pentagon: 5 sides
• Hexagon: 6 sides
• Heptagon: 7 sides
• Octagon: 8 sides
• Nonagon: 9 sides
• Decagon: 10 sides

Regular vs. Irregular Polygons

Polygons can also be regular or irregular.

• Regular Polygon: All sides and angles are equal. For example, a regular hexagon has 6 sides of the same length and each angle is the same.
• Irregular Polygon: Sides and angles are not all the same. For example, an irregular pentagon might have sides of different lengths.

Key Rules for Identifying Polygons

1. Count the Sides: Check how many sides the shape has.
2. Look at the Angles: Are all angles the same? If yes, it’s regular.
3. Check for Straight Lines: Make sure all sides are straight and that the shape is closed.

Tips and Tricks

• Use a ruler to measure the sides if needed.
• Draw lines from one corner to another to see if it forms a polygon.
• Remember that if a shape has curved sides (like a circle), it is NOT a polygon!

Engaging Question

Can you draw a shape with 7 sides? What would you call it?

Questions to Identify and Classify Polygons

Easy Level (1-20)

1. How many sides does a triangle have?
2. Is a square a polygon? Yes or No?
3. Name the polygon with 4 sides.
4. A shape with 5 equal sides is called what?
5. How many sides does a hexagon have?
6. Is a circle a polygon? Yes or No?
7. What do you call a polygon with 8 sides?
8. True or False: A regular polygon has sides of different lengths.
9. What is the name of a polygon with 6 sides?
10. How many angles does a triangle have?
11. Name a polygon with 7 sides.
12. Does a rectangle have equal sides? Yes or No?
13. What type of polygon is a square?
14. Can a polygon have curved sides? Yes or No?
15. What do we call a polygon with 9 sides?
16. Count the sides: Is this shape a polygon? (Draw a triangle)
17. Name a regular polygon with 5 sides.
18. How many sides does a decagon have?
19. Is a trapezoid a polygon? Yes or No?
20. True or False: All squares are rectangles.

Medium Level (21-40)

21. How can you tell if a polygon is regular?
22. Name an irregular polygon with 4 sides.
23. What is the difference between a square and a rectangle?
24. How many sides does a nonagon have?
25. True or False: A hexagon can be regular or irregular.
26. What do you call a polygon with 10 sides?
27. How many angles does a quadrilateral have?
28. Name three types of polygons.
29. Can a shape with 5 sides be irregular? Yes or No?
30. What is the sum of the interior angles of a triangle?
31. How do you classify a shape with sides of different lengths?
32. What is a key feature of all polygons?
33. Name a regular polygon with 8 sides.
34. How many sides does a heptagon have?
35. Can a polygon have only one angle? Yes or No?
36. What are the angles in a regular pentagon?
37. How many sides does the shape below have? (Draw a shape with 6 sides)
38. Can a polygon have a right angle? Yes or No?
39. What is the name of a polygon with 12 sides?
40. True or False: All polygons are closed shapes.

Hard Level (41-60)

41. Calculate the sum of the interior angles of a quadrilateral.
42. How do you determine if a polygon is convex or concave?
43. What would be the name of a polygon with 15 sides?
44. If a hexagon is regular, what is the measure of each interior angle?
45. True or False: A polygon can have an infinite number of sides.
46. What is the difference between a regular triangle and an irregular triangle?
47. How many diagonals can you draw in a pentagon?
48. What is the formula for finding the sum of interior angles of any polygon?
49. If one angle in a regular octagon is 135 degrees, is it regular? Why?
50. Can a polygon have angles greater than 180 degrees? Yes or No?
51. Give an example of a real-world object that is a polygon.
52. How many sides does a dodecagon have?
53. What is the measure of each interior angle in a regular decagon?
54. What can you conclude about a polygon with all sides equal and all angles equal?
55. How many sides does a polygon have if the sum of its interior angles is 540 degrees?
56. What is the relationship between the number of sides and the sum of the interior angles?
57. Can a concave polygon have equal sides? Yes or No?
58. What do you call a polygon with 11 sides?
59. How do you find the measure of each exterior angle in a regular polygon?
60. True or False: A quadrilateral can be both regular and irregular.

Answers

Easy Level Answers

1. 3 sides (Triangle)
2. Yes
3. Quadrilateral
4. Pentagon
5. 6 sides
6. No
7. Octagon
8. True
9. Hexagon
10. 3 angles
11. Heptagon
12. No
13. Regular polygon
14. No
15. Nonagon
16. Yes, it’s a polygon.
17. Pentagon
18. 10 sides
19. Yes
20. True

Medium Level Answers

21. All sides and angles are equal.
22. Trapezoid (or any irregular 4-sided figure)
23. A square has equal sides; a rectangle has opposite sides equal.
24. 9 sides
25. True
26. Decagon
27. 4 angles
28. Triangle, Quadrilateral, Pentagon
29. Yes
30. 180 degrees
31. Irregular polygon
32. Straight sides and closed figure
33. Regular octagon
34. 7 sides
35. No
36. 108 degrees each
37. 6 sides
38. Yes
39. Dodecagon
40. True

Hard Level Answers

41. 360 degrees
42. A convex polygon has no angles greater than 180 degrees; a concave polygon does.
43. Pentadecagon
44. 120 degrees each
45. False
46. A regular triangle has equal sides and angles; an irregular triangle does not.
47. 5 diagonals
48. $$180(n-2)$$ where n is the number of sides.
49. No, because all angles must be equal.
50. Yes
51. House (or a book, or a window)
52. 12 sides
53. 144 degrees
54. It’s a regular polygon.
55. 5 sides (because 540 = $$180(5-2)$$ )
56. $$180(n-2)$$ gives the sum of interior angles.
57. Yes
58. Hendecagon
59. $$\frac{360}{n}$$ where n is the number of sides.
60. True

Feel free to use these explanations and questions in your classroom to help students better understand polygons!