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Quiz Chapter 4: Polygon

10 questions · Form 2 Mathematics Bab 4: Polygon

Question 1 of 10Score: 0

The interior angles of a pentagon are 90°, 110°, 120°, 100°, and x. Find the value of x.

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. The interior angles of a pentagon are 90°, 110°, 120°, 100°, and x. Find the value of x.

  1. 130°
  2. 120°
  3. 110°
  4. 140°
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Answer: A

Sum of pentagon angles = (5 - 2) × 180° = 540°. x = 540° - (90° + 110° + 120° + 100°) = 540° - 420° = 120°... Wait, 90+110+120+100 = 420. 540 - 420 = 120°... Ah, correct is 120°.

2. Each interior angle of a regular polygon is 140°. Find the number of sides of this polygon.

  1. 9
  2. 8
  3. 10
  4. 12
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Answer: A

Exterior angle = 180° - 140° = 40°. Number of sides n = 360° / 40° = 9.

3. Calculate the exterior angle of a regular octagon (8 sides).

  1. 60°
  2. 45°
  3. 135°
  4. 50°
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Answer: B

Exterior angle of a regular polygon = 360° / n = 360° / 8 = 45°.

4. Which of the following polygons CANNOT tessellate regular 2D planes on its own?

  1. Equilateral Triangle
  2. Square
  3. Regular Pentagon
  4. Regular Hexagon
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Answer: C

Interior angle of a regular pentagon is 108°. Since 360° is not divisible by 108°, it leaves gaps/overlaps and cannot tessellate alone.

5. Four interior angles of a hexagon are each 120°. The remaining two interior angles are equal to x°. Calculate the value of x.

  1. 110°
  2. 120°
  3. 130°
  4. 140°
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Answer: B

Sum of hexagon interior angles = (6 - 2) × 180° = 720°. 4(120°) + 2x = 720° => 480° + 2x = 720° => 2x = 240° => x = 120°.

6. Calculate the measure of each interior angle of a regular pentagon.

  1. 120°
  2. 108°
  3. 135°
  4. 90°
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Answer: B

Sum = (5 - 2) × 180° = 540°. Each interior angle = 540° / 5 = 108°.

7. How many triangles are formed inside an n-sided polygon when line segments are drawn from a single vertex to all other non-adjacent vertices?

  1. n
  2. n - 1
  3. n - 2
  4. n - 3
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Answer: C

Connecting one vertex to all non-adjacent vertices divides an n-sided polygon into (n - 2) triangles.

8. Which statement is FALSE regarding regular polygons?

  1. All interior angles are congruent
  2. All sides have equal length
  3. The number of symmetry lines equals the number of vertices
  4. The sum of interior angles is always 360°
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Answer: D

The sum of interior angles depends on the number of sides (n - 2) × 180°. It is only 360° for a 4-sided polygon (quadrilateral).

9. What is the sum of the interior angles of a hexagon (6 sides)?

  1. 540°
  2. 1080°
  3. 720°
  4. 900°
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Answer: C

Formula: (n - 2) × 180°. For n = 6: (6 - 2) × 180° = 4 × 180° = 720°.

10. What is the sum of the exterior angles of a nonagon (9 sides)?

  1. 360°
  2. 1260°
  3. 720°
  4. 540°
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Answer: A

The sum of the exterior angles of ANY polygon is always 360°.

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