Draw an angle of 80° with the help of a protractor. Then construct angles of (i) 40° (ii) 160° and (iii) 120°.
Solution:
Construct an angle 80° i.e. ∠QOA = 180° using a protractor
Steps of Construction
1. Considering O as radius and any radius construct an arc that intersects OA at the point E and OQ at the point F
2. Considering E and F as centres and radius more than half of EF construct an arc that intersects each other at the point F
3. Now join OP
∠POA = 1/2 x 80° = 40°
4. Considering F as centre and radius equal to EF, construct an arc that intersects previous arcs at the point S
5. Join OS.
∠SOA = 2 x 80° = 160°
6. Considering S and F as centre and radius more than half of SF construct an arc that intersects each other at the point R
7. Join OR
∠ROA = ∠ROQ = 40° + 80° = 120°
Thus, the angles are constructed.
✦ Try This: Draw an angle of 60° with the help of a protractor. Then construct angles of (i) 50° (ii) 170° and (iii) 140°
☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 11
NCERT Exemplar Class 9 Maths Exercise 11.3 Problem 3
Draw an angle of 80° with the help of a protractor. Then construct angles of (i) 40°, (ii) 160° and (iii) 120°.
Summary:
An angle of 80° is drawn with the help of a protractor. Then the angles (i) 40° (ii) 160° and (iii) 120° are constructed
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