8th Maths 4.2

Chapter 4

Practical Geometry

NCERT Class 8th Solution of Exercise 4.1

NCERT Class 8th Solution of Exercise 4.3

NCERT Class 8th Solution of Exercise 4.4

NCERT Class 8th Solution of Exercise 4.5

EXERCISE 4.2

Q1. Construct the following quadrilaterals.
i) quadrilateral LIFT
LI=4 cm
IF=3 cm
TL=2.5 cm
LF 4.5 cm
IT=4 cm

ii) Quadrilateral GOLD

OL=7.5 cm
GL=6cm
GD=6 cm
LD=5 cm
OD = 10 cm

iii) Rhombus BEND
BN=5.6 cm
DE=6.5 cm

`text{Solution:}`

i) `text{quadrilateral LIFT}`
`text{LI=4 cm}`
`text{IF=3 cm}`
`text{TL=2.5 cm}`
`text{LF 4.5 cm}`
`text{IT=4 cm}`

`text{Rough sketch of a quadrilateral LIFT}`

`text{Fair sketch of a quadrilateral LIFT}`

`text{Step of Construction:}`

1) `text{Draw LI = 4 cm.}`

2) `text{Draw an arc with a center I of radius}``text{ 3 cm.}`

3) `text{Draw another arc with a center L of radius}``text{ 4.5 cm to meet the previous arc at F.}` 

4) `text{Draw an arc with center L of radius 2.5 cm.}`

5) `text{Draw another arc with a center I of radius}``text{ 4 cm to meet the previous arc at T.}`

6) `text{Join IF, FT, TL, IT and LF}`

7) `text{We get quadrilateral LIFT.}`

ii) `text{Quadrilateral GOLD}`

`text{OL=7.5 cm}`
`text{GL=6cm}`
`text{GD=6 cm}`
`text{LD=5 cm}`
`text{OD = 10 cm}`

`text{Rough sketch of a quadrilateral GOLD}`

`text{Fair sketch of a quadrilateral GOLD}`

`text{Step of Construction:}`

1) `text{Draw OL = 7.5 cm.}`

2) `text{Draw an arc with a center O of radius}``text{ 10 cm.}`

3) `text{Draw another arc with a center L of radius}``text{ 5 cm to meet the previous arc at D.}` 

4) `text{Draw an arc with center L of radius 6 cm.}`

5) `text{Draw another arc with a center D of radius}``text{ 6 cm to meet the previous arc at G.}`

6) `text{Join LD, DG, GO, GL and OD}`

7) `text{We get quadrilateral GOLD.}`

iii) `text{Rhombus BEND}`
`text{BN=5.6 cm}`
`text{DE=6.5 cm}`

`text{Rough sketch of a rhombus BEND}`

`text{Fair sketch of a rhombus BEND}`

`text{Step of Construction:}`

`[text{Diagonal of a rhombus bisect each other at}``text{ the right angle.}]`

1) `text{Draw BN = 5.6 cm.}`

2) `text{Draw perpendicular bisector of BN at O.}`

3) `text{Draw two arcs with a center O of radius}``1/2text{×DE =}``1/2text{×6.5 = 3.25 cm}``text{ to meet the perpendicular bisector at D and E.}` 

5) `text{Join BE, EN, ND, and DB}`

6) `text{We get rhombus BEND.}`