NCERT Solutions Class 8th Maths Chapter 4 Practical Geometry Exercise 4.5

NCERT Solutions Class 8th Maths Chapter 4 Practical Geometry

NCERT Solutions Class 8th Maths Chapter 4 Practical Geometry

Chapter – 4

Practical Geometry

Exercise 4.5

1. The square READ with RE = 5.1 cm

Solution

All the sides of a square are of the same measure and also all the interior angles of a square are of 90º measure. Therefore, the given square READ can be drawn as follows.

Rough Figure:

(1) Draw a line segment RE of 5.1 cm and an angle of 90º at points R and E.

(2) As vertex A and D are 5.1 cm away from vertex E and R respectively, cut line segments EA and RD, each of 5.1 cm from these rays.

(3) Join D to A.

READ is the required square.

2. A rhombus whose diagonals are 5.2 cm and 6.4 cm long.

Solution In a rhombus, diagonals bisect each other at 90º. ∴, the given rhombus ABCD can be drawn as follows.

Rough Figure:

(1) Draw a line segment AC of 5.2 cm and draw its perpendicular bisector. Let it intersect the line segment AC at point O.

(2) Draw arcs of 6.4/2 = 3.2 on both sides of this perpendicular bisector. Let the arcs intersect the perpendicular bisector at point B and D.

(3) Join points B and D with points A and C.

ABCD is the required rhombus.

3. A rectangle with adjacent sides of lengths 5 cm and 4 cm.

Solution Opposite sides of a rectangle have their lengths of the same measure and also, all the interior angles of a rectangle are of 90º measure. The given rectangle ABCD may be drawn as follows.

Rough figure:

(1) Draw a line segment AB of 5 cm and an angle of 90º at point A and B.

(2) As vertex C and D are 4 cm away from vertex B and A respectively, cut line segments AD and BC, each of 4 cm, from these rays.

(3) Join D to C.

ABCD is the required rectangle.

4. A parallelogram OKAY where OK = 5.5 cm and KA = 4.2 cm. 

Solution Opposite sides of a parallelogram are equal and parallel to each other. The given parallelogram OKAY can be drawn as follows.

Rough Figure:

(1) Draw a line segment OK of 5.5 cm and a ray at point K at a convenient angle.

(2) Draw a ray at point O parallel to the ray at K. As the vertices, A and Y, are 4.2 cm away from the vertices K and O respectively, cut line segments KA and OY, each of 4.2 cm, from these rays.

(3) Join Y to A.

OKAY is the required rectangle.

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