This document provides answers and solutions to mathematics problems and activities from a 9th standard practical book. It contains answers to two parts of mathematics – Part I and Part II. Part I covers chapters 1 to 7 with activities on topics like number systems, algebra, geometry, trigonometry etc. Part II also covers similar topics in chapters 1 to 9 with activities involving constructions, proofs and calculations. The document provides step-by-step workings and solutions to multiple choice and descriptive questions from each chapter in a systematic manner to help students understand different mathematical concepts.
SECTION 1 : HOME ASSIGNMENTS 1
VIKAS MATHEMATICS PRACTICAL BOOK : STD. IX
ANSWERS
SECTION 1 : HOME ASSIGNMENTS
MATHEMATICS PART - I
Chapter 1 :
Activity 1 (A) :
{2}
,
2
,
2
,
.
Activity 1 (B) :
n (B)
,
n (AWB)
,
29
,
7
,
8
,
21
.
Activity 2 (A) :
n (AXB)
,
36
,
36
,
12
.
Activity 2 (B) :
1, 2, 3, 4, 5, 6, 7, 8, 9, 10
,
10
,
2, 3, 4, 5
,
4, 5, 9
,
4, 5, 10
,
2
.
Chapter 2 :
Activity 3 (A) :
25
,
5
,
9 4 5
,
10
.
Activity 3 (B) :
10
,
0.7.
,
7.7.
,
0.7.
,
7
,
7
9
.
Activity 4 (A) :
1
,
6
,
4
,
4
3
.
Activity 4 (B) :
e5 e3
,
e5 e3
,
e5 e3
,
2
,
( e3)
2
,
8 2 e
f
15
2
.
Chapter 3 :
Activity 5 (A) :
x
3
2x
2
2
,
1
,
x
8
,
2
.
Activity 5 (B) :
1
,
5
,
2
,
2
,
y
2
2y 3
,
2
.
Activity 6 (A) :
1
,
2
,
2
,
7
.
Activity 6 (B) :
3x
,
x
,
e3
,
e3
,
1
,
e3x 1
.
Chapter 4 :
Activity 7 (A) :
e
f
35
,
e
f
81
,
<
,
<
.
Activity 7 (B) :
c
,
b
,
b
,
c d
,
a b
,
d
.
Activity 8 (A) :
36
,
22
,
16
,
2a
2b 2c
.
Activity 8 (B) :
m
2
,
x y
,
x y
,
(x y)
2
,
x
2
y
2
,
(x y)
.
Chapter 5 :
Activity 9 (A) :
10
,
( 3, 10)
,
( 5)
,
( 5, 12)
.
Activity 9 (B) :
8y
,
16
,
(x y)
,
2
,
2
,
1
.
Activity 10 (A) :
y x 7
,
x y 53
,
60
,
30
.
Activity 10 (B) :
7x
,
21
,
3
,
15
,
6
,
2
.
Chapter 6 :
Activity 11 (A) :
6000
,
10000
,
6000
,
4000
.
Activity 11 (B) :
520000
,
400000
,
120000
,
48000
,
120000
,
72000
.
Activity 12 (A) :
10000
,
15000
,
10000
,
15000
.
Activity 12 (B) :
N
,
100
,
220000
,
2200
,
2200
,
24200
.
Chapter 7 :
Activity 13 (A) :
15
,
20
,
35
,
17.5
.
Activity 13 (B) :
12
,
10 15
,
24
,
8
,
8
,
42
.
Activity 14 (A) :
f
i
,
525
,
25
,
21
.
Activity 14 (B) :
20 30
,
20
,
20
,
30
,
34
,
36
.
2 VIKAS MATHEMATICS PRACTICAL BOOK : STANDARD IX
MATHEMATICS PART - II
Chapter 1 :
Activity 1 (A) :
Given : O is a point on line AB. Ð AOC X Ð COB
,
To prove : Ð AOC Ð COB 90°
,
Converse of the statement : If the angles in a
linear pair are right angles then they are
congruent.
.
Activity 1 (B) :
d (B, C)
,
7.5
,
18
,
18
,
7.5
,
10.5
.
Activity 2 (A) :
>
,
( x 3 )
,
( x 3 )
,
6
.
Activity 2 (B) :
linear
,
180°
,
3x°
,
120°
,
60°
,
60°
.
Chapter 2 :
Activity 3 (A) :
110°
,
181°
,
are not
,
is not
.
Activity 3 (B) :
Ð e
,
Ð b
,
Ð e
,
Ð f
,
Ð d
,
Ð c
.
Activity 4 (A) :
Ð ADC
,
56 °
,
Ð CPD
,
80 °
.
Activity 4 (B) :
Vertically opposite angles
,
20 °
,
180 °
,
20 °
,
20
,
160
.
Chapter 3 :
Activity 5 (A) : (i)
SSS
, (ii)
SAS
, (iii)
ASA
,
(iv)
hypotenuse-side
.
Activity 5 (B) :
QPR
,
70 °
,
180 °
,
70 °
,
20 °
,
90 °
.
Activity 6 (A) :
seg CB
,
seg AD
,
Common side
,
SSS test
.
Activity 6 (B) :
Vertically opposite angles
,
TR
,
SAS
,
Ð TSR
,
Ð TQP
,
seg SR
.
Chapter 4 :
Activity 7 (A) and (B) and 8 (A) and (B)
Students should complete the constructions.
Chapter 5 :
Activity 9 (A) :
AB
2
,
BC
2
,
AC
2
,
10 cm
.
Activity 9 (B) :
Ð FDE
,
65
,
5
,
Ð FDG
,
35
,
7
.
Activity 10 (A) :
180 °
,
40 °
,
220°
,
110 °
.
Activity 10 (B) :
2
3
,
2
3
,
3
2
,
9
,
9
,
3
.
Chapter 6 :
Activity 11 (A) :
BM
,
QM
,
BM
,
QM
.
Activity 11 (B) :
PQ
,
24
,
12
,
13
,
OM
,
5 cm
.
Activity 12 (A) :
Radii of the same circle
Hypotenuse side test
Perpendicular drawn from the
centre of the circle to the chord
bisects the chord.
CD
.
Activity 12 (B) :
AB
,
16 cm
,
8
,
8
2
,
289
,
17 cm
.
Chapter 7 :
Activity 13 (A) :
(
0
,
4
)
,
y 3
,
3
.
Activity 13 (B) :
1
,
( 0, 1 )
,
0
,
1, 0
,
3
,
3, 2
.
Activity 14 (A) :
3
,
3
,
y 3
,
No
.
Chapter 8 :
Activity 15 (A) :
AB
,
x
,
2x
,
1
2
.
Activity 15 (B) :
70
,
60
,
50
,
45
,
80
,
63
.
SECTION 1 : HOME ASSIGNMENTS 3
Activity 16 (A) :
1
,
1
m2
,
1
2
,
1
.
Activity 16 (B) :
LM
LN
,
LM
LN
,
MN
LM
,
LM
MN
,
MN
LN
,
MN
LN
.
Chapter 9 :
Activity 17 (A) :
7.5 cm
,
l
3
,
7.5
,
421.875
.
Activity 17 (B) :
1
3
r h
2
,
753.60
,
12
,
3
,
3.14
,
5
.
Activity 18 (A) :
4 r
2
,
4 3.14
,
225
,
15
.
Activity 18 (B) :
4l
2
,
4.5
,
81
,
6l
2
,
4.5
,
121.50
.
