# NCERT Class 9 Solutions: Constructions (Chapter 11) Exercise 11.1 – Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Constructions of angle

Q-4 Construct the following angles and verify by measuring them by a protractor:

1.

2.

3.

Solution:

i) Step of Construction:

- Draw a OA ray
- Construct
- Construct
- Bisect so that
- So, that
- Verification:
- , with the protractor, we find

ii) Step of Construction:

- Draw a line segment XA.
- Construct and
- ()

- Bisect angle SAZ it bisector AR
- So that,
- Then in the angle of

iii) Step of Construction:

- Draw
- Then

- Draw the bisector of
- Construct,
- So that,
- Then

Q-5 Construct an equilateral triangle, given its side and justify the construction.

Solution:

- Take a ray CD with initial point C
- C as centre and radius ()
- Draw an arc of a circle, which intersects CD
- Taking B as centre and with the same radius as before
- Draw an arc intersecting the previously drawn arc, say at a point C
- Join CA and BA

Then is the required triangle with side

Justification:

(Sum of the angles of a triangle)

(Sides opposite to equal angles are equal)