GSEB Class 6 Maths Solutions Chapter 5 Understanding Elementary Shapes Exercise 5.3

Question 1. Match the following:
(i) Straight angle
(a) Less than one-fourth of a revolution
(ii) Right angle
(b) More than half a revolution
(iii) Acute angle
(c) Half of a revolution
(iv) Obtuse angle
(d) One-fourth of a revolution
(v) Reflex angle
(e) Between \( \frac { 1 }{ 4 } \) and \( \frac { 1 }{ 2 } \) of a revolution
(f) One complete a revolution
Answer:
(i) Straight angle: (c) Half of a revolution
(ii) Right angle: (d) One-fourth of a revolution
(iii) Acute angle: (a) Less than one-fourth of a revolution
(iv) Obtuse angle: (e) Between \( \frac { 1 }{ 4 } \) and \( \frac { 1 }{ 2 } \) of a revolution
(v) Reflex angle: (b) More than half a revolution
In simple words: Match each angle type with its definition based on a revolution. A straight angle is half a turn, a right angle is a quarter turn, an acute angle is less than a quarter turn, an obtuse angle is between a quarter and half turn, and a reflex angle is more than half a turn.

Exam Tip: Remember the definitions of each angle type in terms of a full revolution (360 degrees) to accurately match them.

Question 2. Classify each one of the following angles as right, straight, acute, obtuse or reflex:
Answer:
(a) Acute angle
(b) Obtuse angle
(c) Right angle
(d) Reflex angle
(e) Straight angle
(f) Acute angle
In simple words: Look at each picture of an angle. If it is smaller than a corner, it's acute. If it is exactly like a corner, it's right. If it is bigger than a corner but less than a straight line, it's obtuse. If it forms a straight line, it's straight. If it is bigger than a straight line, it's reflex.

Exam Tip: Use a protractor or a corner of a book to visually check and classify angles, remembering that a right angle is 90 degrees, a straight angle is 180 degrees, and a reflex angle is between 180 and 360 degrees.