CBSE Class 5 Mathematics Shapes And Angles Worksheet Set 04

Competency- Formation of Numbers

Question. Right angle = ____________________ degrees
Answer: \( 90 \) (or \( 90^\circ \))

Question. An obtuse angle is more than a ____________ angle.
Answer: right

Question. \( 2 \times \text{Right angle} = \) ________________ degrees.
Answer: \( 180 \) (or \( 180^\circ \))

Competency: Understanding Basic Concepts

Question. What measure (in degrees) should be added to the following to make them a right angle?
i) \( 34^\circ \)
ii) \( 16^\circ \)
iii) \( 19^\circ \)
iv) \( 28^\circ \)
v) \( 78^\circ \)
vi) \( 38^\circ \)
vii) 84
viii) 90
Answer:
A right angle measures \( 90^\circ \). To find the required measure, subtract the given angle from \( 90^\circ \):
i) \( 90^\circ - 34^\circ = 56^\circ \)
ii) \( 90^\circ - 16^\circ = 74^\circ \)
iii) \( 90^\circ - 19^\circ = 71^\circ \)
iv) \( 90^\circ - 28^\circ = 62^\circ \)
v) \( 90^\circ - 78^\circ = 12^\circ \)
vi) \( 90^\circ - 38^\circ = 52^\circ \)
vii) \( 90^\circ - 84^\circ = 6^\circ \)
viii) \( 90^\circ - 90^\circ = 0^\circ \)

Competency :Ability to Compute

Question. Measure the following angles:-
Answer:
1. Top-left angle: Obtuse angle (approximately \( 135^\circ \))
2. Top-right angle: Right angle (\( 90^\circ \))
3. Bottom-left angle: Acute angle (approximately \( 45^\circ \))
4. Bottom-right angle: Straight angle (\( 180^\circ \))