Vidaara.orgClass 6 · Mathematics
CodeVID-M06-11-TRI-01
Angle Sum of a Triangle - Assignment
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 angles of a triangle sum to:
- A.$90^\circ$
- B.$180^\circ$
- C.$270^\circ$
- D.$360^\circ$
2.
Each angle of an equilateral triangle is:
- A.$45^\circ$
- B.$60^\circ$
- C.$90^\circ$
- D.$30^\circ$
3.
A right triangle has one angle of:
- A.$45^\circ$
- B.$60^\circ$
- C.$90^\circ$
- D.$120^\circ$
4.
An exterior angle equals the sum of the two:
- A.adjacent angles
- B.opposite interior angles
- C.right angles
- D.exterior angles
5.
If two angles are $50^\circ$ and $60^\circ$, the third is:
- A.$60^\circ$
- B.$70^\circ$
- C.$80^\circ$
- D.$90^\circ$
Section B — Short Answer (2 marks)
4 × 2 = 8 marks
6.
Two angles are $40^\circ$ and $75^\circ$. Find the third.
7.
Each angle of an equilateral triangle is:
8.
A right triangle has one angle of:
9.
Two angles are $90^\circ$ and $45^\circ$. Find the third.
Section C — Short Answer (3 marks)
4 × 3 = 12 marks
10.
The angles are in ratio $1:2:3$. Find them.
11.
Two angles are equal and the third is $80^\circ$. Find each equal angle.
12.
The angles are in ratio $2:3:4$. Find them.
13.
An exterior angle is $120^\circ$ with one opposite interior angle $50^\circ$. Find the other.
Section D — Long Answer (5 marks)
2 × 5 = 10 marks
14.
The angles of a triangle are $x,\ (x+10),\ (x+20)$. Find all three.
15.
In a triangle, two angles are equal and each is twice the third. Find all three angles.
Answer Key
Section A — Multiple Choice Questions
- (B) $180^\circ$
- (B) $60^\circ$
- (C) $90^\circ$
- (B) opposite interior angles
- (B) $70^\circ$
Section B — Short Answer (2 marks)
- $65^\circ$.
- $60^\circ$.
- $90^\circ$.
- $45^\circ$.
Section C — Short Answer (3 marks)
- $30^\circ, 60^\circ, 90^\circ$.
- $50^\circ$.
- $40^\circ, 60^\circ, 80^\circ$.
- $70^\circ$.
Section D — Long Answer (5 marks)
- $50^\circ, 60^\circ, 70^\circ$.
- $36^\circ, 72^\circ, 72^\circ$.
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