NCERT Solutions Class 8th Maths Chapter 4 Practical Geometry Exercise 4.3

NCERT Solutions Class 8th Maths Chapter 4 Practical Geometry

NCERT Solutions Class 8th Maths Chapter 4 Practical Geometry

Chapter – 4

Practical Geometry

Exercise 4.3

1. Construct the following quadrilaterals.
(i) Quadrilateral MORE MO = 6 cm
OR = 4.5 cm
∠M = 60°
∠O = 105°
∠R = 105°

Solution Rough Figure:

(1) Draw a line segment MO of 6 cm and an angle of 105º at point O. As vertex R is 4.5 cm away from the vertex O, cut a line segment OR of 4.5 cm from this ray.

(2) Again, draw an angle of 105º at point R.

(3) Draw an angle of 60º at point M. Let this ray meet the previously drawn ray from R at point E.

MORE is the required quadrilateral.

(ii) Quadrilateral PLAN PL = 4 cm
LA = 6.5 cm
∠P = 90°
∠A = 110°
∠N = 85°

Solution
The sum of the angles of a quadrilateral is 360°. In quadrilateral PLAN,
∠P + ∠L + ∠A + ∠N = 360° 90° + ∠L + 110° + 85° = 360°
285° + ∠L = 360°
∠L = 360° − 285° = 75°

Rough Figure:

(1) Draw a line segment PL of 4 cm and draw an angle of 75º at point L. As vertex A is 6.5 cm away from vertex L, cut a line segment LA of 6.5 cm from this ray.

(2) Again draw an angle of 110º at point A.

(3) Draw an angle of 90º at point P. This ray will meet the previously drawn ray from A at point N.

PLAN is the required quadrilateral.

(iii) Parallelogram HEAR HE = 5 cm
EA = 6 cm
∠R = 85°

Solution Rough Figure:

(1) Draw a line segment HE of 5 cm and an angle of 85º at point E. As vertex A is 6 cm away from vertex E, cut a line segment EA of 6 cm from this ray.

(2) Vertex R is 6 cm and 5 cm away from vertex H and A respectively. By taking radius as 6 cm and 5 cm, draw arcs from point H and A respectively. These will be intersecting each other at point R.

(3) Join R to H and A.

HEAR is the required quadrilateral.

(iv) Rectangle OKAY
OK = 7 cm KA = 5 cm

Solution Rough Figure:

(1) Draw a line segment OK of 7 cm and an angle of 90º at point K. As vertex A is 5 cm away from vertex K, cut a line segment KA of 5 cm from this ray.

(2) Vertex Y is 5 cm and 7 cm away from vertex O and A respectively. By taking
radius as 5 cm and 7 cm, draw arcs from point O and A respectively. These will be intersecting each other at point Y.

(3) Join Y to A and O.

OKAY is the required quadrilateral.

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