NCERT Exemplar Solutions
Class 6 - Mathematics - Unit 9: Symmetry and Practical Geometry - True or False Questions
Question 52

Question. 52

Using only the two set-squares of the geometry box, an angle of 40° can be drawn.

Answer:

false

Detailed Answer with Explanation:

Why this is false (step by step):

1) In a standard geometry box there are two set-squares:

  • One is a 45°–45°–90° triangle.
  • The other is a 30°–60°–90° triangle.

2) Using only these two set-squares (no protractor/compass), we can make angles that are sums or differences of 30° and 45°, and right angles.

(45^circ)

(30^circ,;60^circ)

(90^circ)

(45^circ + 30^circ = 75^circ)

(60^circ - 45^circ = 15^circ)

3) So the acute angles we can get are in steps of 15°:

(0^circ,;15^circ,;30^circ,;45^circ,;60^circ,;75^circ,;90^circ,dots)

4) Now check 40°:

(40^circ) is not a multiple of (15^circ).

(40 div 15) is not an integer.

Conclusion: With only the two set-squares, you cannot draw exactly 40°. Therefore, the statement is false.

NCERT Exemplar Solutions Class 6 – Mathematics – Unit 9: Symmetry and Practical Geometry – True or False Questions | Detailed Answers