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Vidaara.orgClass 8 · Mathematics
CodeVID-M08-12-IEA-01
Interior & Exterior Angles - Assignment
Chapter: Polygons
Topic: Interior and Exterior Angles of Polygons
Maximum Marks: 35
Time: 75 minutes
Name: ____________________ Roll No.: __________ Date: ____________

General Instructions

  • All questions are compulsory.
  • Section A carries 1 mark each, Section B 2 marks, Section C 3 marks and Section D 5 marks.
  • Show all working for Sections B, C and D. Only final answers are given at the end — for full solutions, raise your doubts with your teacher.
Section A — Multiple Choice Questions 5 × 1 = 5 marks
1.
The sum of interior angles of an $n$-gon is:
  • A.$n\times180^\circ$
  • B.$(n-2)\times180^\circ$
  • C.$360^\circ$
  • D.$\tfrac{360^\circ}{n}$
2.
The sum of exterior angles of any polygon is:
  • A.$180^\circ$
  • B.$360^\circ$
  • C.$(n-2)180^\circ$
  • D.$90^\circ$
3.
Each interior angle of a regular $n$-gon is:
  • A.$\tfrac{(n-2)180^\circ}{n}$
  • B.$\tfrac{360^\circ}{n}$
  • C.$(n-2)180^\circ$
  • D.$180^\circ n$
4.
Each exterior angle of a regular $n$-gon is:
  • A.$\tfrac{360^\circ}{n}$
  • B.$(n-2)180^\circ$
  • C.$\tfrac{180^\circ}{n}$
  • D.$360^\circ n$
5.
Interior $+$ exterior angle at a vertex is:
  • A.$90^\circ$
  • B.$180^\circ$
  • C.$360^\circ$
  • D.$270^\circ$
Section B — Short Answer (2 marks) 4 × 2 = 8 marks
6.
Find the interior angle sum of a quadrilateral.
7.
Find the interior angle sum of a pentagon.
8.
Find each exterior angle of a regular hexagon.
9.
The exterior angles of any polygon sum to:
Section C — Short Answer (3 marks) 4 × 3 = 12 marks
10.
Find the interior angle sum of a hexagon.
11.
Find each interior angle of a regular pentagon.
12.
Find each exterior angle of a regular octagon.
13.
The interior angle of a regular polygon is $150^\circ$. Find its exterior angle.
Section D — Long Answer (5 marks) 2 × 5 = 10 marks
14.
Find each interior angle of a regular hexagon and verify it with the exterior angle.
15.
A regular polygon has each exterior angle $36^\circ$. Find the number of sides and the interior angle sum.

Answer Key

Section A — Multiple Choice Questions
  1. (B) $(n-2)\times180^\circ$
  2. (B) $360^\circ$
  3. (A) $\tfrac{(n-2)180^\circ}{n}$
  4. (A) $\tfrac{360^\circ}{n}$
  5. (B) $180^\circ$
Section B — Short Answer (2 marks)
  1. $360^\circ$.
  2. $540^\circ$.
  3. $60^\circ$.
  4. $360^\circ$.
Section C — Short Answer (3 marks)
  1. $720^\circ$.
  2. $108^\circ$.
  3. $45^\circ$.
  4. $30^\circ$.
Section D — Long Answer (5 marks)
  1. Interior $120^\circ$, exterior $60^\circ$; $120^\circ+60^\circ=180^\circ$.
  2. $10$ sides; sum $1440^\circ$.
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