Unit Test (Solutions): Angles as Turns | Mathematics (Maths Mela) Class 5 - New NCERT PDF Download

Time: 1 hour M.M. 20 
Attempt all questions. 

• Question numbers 1 to 5 carry 1 mark each. 
• Question numbers 6 to 8 carry 2 marks each. 
• Question numbers  9 to 11 carry 3 marks each. 

Q1. A straight angle is equal to how many degrees? (1 Mark)
(a) 90°
(b) 120°
(c) 150°
(d) 180°
Ans: (d)

• A straight angle is formed when the two arms of an angle lie in exactly opposite directions, forming a straight line.

• Measure of a straight angle = 180°.

Q2. Three quarter turns in the same direction are equal to: (1 Mark)
(a) Half turn
(b) Full turn
(c) Straight angle
(d) Reflex angle
Ans: (d)

• 1 quarter turn = 90°

• 3 quarter turns = 3 × 90° = 270°

• An angle of 270° is a reflex angle (greater than 180° but less than 360°).

Q3. How many half turns make two full turns? (1 Mark)
(a) 2
(b) 3
(c) 4
(d) 6
Ans: (c)

• 1 half turn = 180°

• 1 full turn = 360°

• 2 full turns = 2 × 360° = 720°

• Number of half turns in 720° = 720 ÷ 180 = 4

Q4. How many degrees are there in one and a half turns? (1 Mark)
(a) 270°
(b) 360°
(c) 450°
(d) 540°
Ans: (c)

• 1 turn = 360°

• 1 and a half turns = 1.5 × 360° = 540°

Q5. An acute angle is always: (1 Mark)
(a) Less than 90°
(b) Equal to 90°
(c) Between 90° and 180°
(d) More than 180°
Ans: (a)

An acute angle is less than 90°.

Q6. For each turn, write the measure in degrees and the type of angle: (2 Marks)

(a) 2 quarter turns clockwise → ______ ° → type: __________
(b) 1 full turn anti-clockwise → ______ ° → type: __________
(c) 5/6 of a full turn → ______ ° → type: __________
(d) 1 quarter turn anti-clockwise → ______ ° → type: __________

Ans:
(a) 180° → Straight angle
(b) 360° → Full angle
(c) 300° → Reflex angle
(d) 90° → Right angle

Q7. A car is facing North. It makes the following sequence of turns: (2 Marks)

(i) 1 half turn clockwise
(ii) 1 quarter turn anti-clockwise
(iii) 1 quarter turn clockwise

(a) What direction is it facing now? __________
(b) What is the net turn (in degrees) relative to the start? __________°

Ans: (a) Starting direction = North

• (i) Half turn clockwise = 180° → Facing South

• (ii) Quarter turn anti-clockwise = 90° → Facing East

• (iii) Quarter turn clockwise = 90° → Facing South

 Final direction = South
(b) Net turn = 180° (since it ends facing opposite to the start)

Q8: A toy car starts facing East. It makes two quarter turns anticlockwise. Which direction is it facing now? (2 Marks)

Ans:  Starting direction = East
Two quarter turns anticlockwise = 2 × 90° = 180°

East → North → West

Answer: West

Q9. Identify the type of angles: (3 Marks)

(a) 35° → ________
(b) 135° → ________
(c) 270° → ________

Ans:
(a) Acute angle
(b) Obtuse angle
(c) Reflex angle

Q10: Draw angles of the following measures: (3 Marks)

(a) 140°
(b) 82°
(c) 35°

Ans:
(a) 140°(b) 82°(c) 35°

Q11: A robot starts facing North. It makes three quarter turns clockwise. Which direction is it facing now? (3 Marks)
Solution:

• Starting direction = North

• Three quarter turns clockwise = 3 × 90° = 270°

• North → East → South → West
  Answer: West