Page 1
1. Write down each pair of adjacent angles shown in fig. 13.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles
Therefore the adjacent angles in given figure are:
?DOC and ?BOC
?COB and ?BOA
2. In Fig. 14, name all the pairs of adjacent angles.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles.
In fig (i), the adjacent angles are
?EBA and ?ABC
?ACB and ?BCF
?BAC and ?CAD
In fig (ii), the adjacent angles are
Page 2
1. Write down each pair of adjacent angles shown in fig. 13.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles
Therefore the adjacent angles in given figure are:
?DOC and ?BOC
?COB and ?BOA
2. In Fig. 14, name all the pairs of adjacent angles.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles.
In fig (i), the adjacent angles are
?EBA and ?ABC
?ACB and ?BCF
?BAC and ?CAD
In fig (ii), the adjacent angles are
?BAD and ?DAC
?BDA and ?CDA
3. In fig. 15, write down
(i) Each linear pair
(ii) Each pair of vertically opposite angles.
Solution:
(i) The two adjacent angles are said to form a linear pair of angles if their non – common
arms are two opposite rays.
?1 and ?3
?1 and ?2
?4 and ?3
?4 and ?2
?5 and ?6
?5 and ?7
?6 and ?8
?7 and ?8
(ii) The two angles formed by two intersecting lines and have no common arms are
called vertically opposite angles.
?1 and ?4
?2 and ?3
?5 and ?8
?6 and ?7
4. Are the angles 1 and 2 given in Fig. 16 adjacent angles?
Page 3
1. Write down each pair of adjacent angles shown in fig. 13.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles
Therefore the adjacent angles in given figure are:
?DOC and ?BOC
?COB and ?BOA
2. In Fig. 14, name all the pairs of adjacent angles.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles.
In fig (i), the adjacent angles are
?EBA and ?ABC
?ACB and ?BCF
?BAC and ?CAD
In fig (ii), the adjacent angles are
?BAD and ?DAC
?BDA and ?CDA
3. In fig. 15, write down
(i) Each linear pair
(ii) Each pair of vertically opposite angles.
Solution:
(i) The two adjacent angles are said to form a linear pair of angles if their non – common
arms are two opposite rays.
?1 and ?3
?1 and ?2
?4 and ?3
?4 and ?2
?5 and ?6
?5 and ?7
?6 and ?8
?7 and ?8
(ii) The two angles formed by two intersecting lines and have no common arms are
called vertically opposite angles.
?1 and ?4
?2 and ?3
?5 and ?8
?6 and ?7
4. Are the angles 1 and 2 given in Fig. 16 adjacent angles?
Solution:
No, because they don’t have common vertex.
5. Find the complement of each of the following angles:
(i) 35
o
(ii) 72
o
(iii) 45
o
(iv) 85
o
Solution:
(i) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 35
o
= 55
o
(ii) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
0
– 72
o
= 18
o
(iii) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 45
o
= 45
o
(iv) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 85
o
= 5
o
6. Find the supplement of each of the following angles:
(i) 70
o
(ii) 120
o
(iii) 135
o
(iv) 90
o
Page 4
1. Write down each pair of adjacent angles shown in fig. 13.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles
Therefore the adjacent angles in given figure are:
?DOC and ?BOC
?COB and ?BOA
2. In Fig. 14, name all the pairs of adjacent angles.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles.
In fig (i), the adjacent angles are
?EBA and ?ABC
?ACB and ?BCF
?BAC and ?CAD
In fig (ii), the adjacent angles are
?BAD and ?DAC
?BDA and ?CDA
3. In fig. 15, write down
(i) Each linear pair
(ii) Each pair of vertically opposite angles.
Solution:
(i) The two adjacent angles are said to form a linear pair of angles if their non – common
arms are two opposite rays.
?1 and ?3
?1 and ?2
?4 and ?3
?4 and ?2
?5 and ?6
?5 and ?7
?6 and ?8
?7 and ?8
(ii) The two angles formed by two intersecting lines and have no common arms are
called vertically opposite angles.
?1 and ?4
?2 and ?3
?5 and ?8
?6 and ?7
4. Are the angles 1 and 2 given in Fig. 16 adjacent angles?
Solution:
No, because they don’t have common vertex.
5. Find the complement of each of the following angles:
(i) 35
o
(ii) 72
o
(iii) 45
o
(iv) 85
o
Solution:
(i) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 35
o
= 55
o
(ii) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
0
– 72
o
= 18
o
(iii) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 45
o
= 45
o
(iv) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 85
o
= 5
o
6. Find the supplement of each of the following angles:
(i) 70
o
(ii) 120
o
(iii) 135
o
(iv) 90
o
Solution:
(i) The two angles are said to be supplementary angles if the sum of those angles is 180
o
Therefore supplementary angle for the given angle is
180
o
– 70
o
= 110
o
(ii) The two angles are said to be supplementary angles if the sum of those angles is 180
o
Therefore supplementary angle for the given angle is
180
o
– 120
o
= 60
o
(iii) The two angles are said to be supplementary angles if the sum of those angles is
180
o
Therefore supplementary angle for the given angle is
180
o
– 135
o
= 45
o
(iv) The two angles are said to be supplementary angles if the sum of those angles is
180
o
Therefore supplementary angle for the given angle is
180
o
– 90
o
= 90
o
7. Identify the complementary and supplementary pairs of angles from the following
pairs:
(i) 25
o
, 65
o
(ii) 120
o
, 60
o
(iii) 63
o
, 27
o
(iv) 100
o
, 80
o
Solution:
(i) 25
o
+ 65
o
= 90
o
so, this is a complementary pair of angle.
(ii) 120
o
+ 60
o
= 180
o
so, this is a supplementary pair of angle.
(iii) 63
o
+ 27
o
= 90
o
so, this is a complementary pair of angle.
(iv) 100
o
+ 80
o
= 180
o
so, this is a supplementary pair of angle.
8. Can two obtuse angles be supplementary, if both of them be
(i) Obtuse?
(ii) Right?
Page 5
1. Write down each pair of adjacent angles shown in fig. 13.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles
Therefore the adjacent angles in given figure are:
?DOC and ?BOC
?COB and ?BOA
2. In Fig. 14, name all the pairs of adjacent angles.
Solution:
The angles that have common vertex and a common arm are known as adjacent angles.
In fig (i), the adjacent angles are
?EBA and ?ABC
?ACB and ?BCF
?BAC and ?CAD
In fig (ii), the adjacent angles are
?BAD and ?DAC
?BDA and ?CDA
3. In fig. 15, write down
(i) Each linear pair
(ii) Each pair of vertically opposite angles.
Solution:
(i) The two adjacent angles are said to form a linear pair of angles if their non – common
arms are two opposite rays.
?1 and ?3
?1 and ?2
?4 and ?3
?4 and ?2
?5 and ?6
?5 and ?7
?6 and ?8
?7 and ?8
(ii) The two angles formed by two intersecting lines and have no common arms are
called vertically opposite angles.
?1 and ?4
?2 and ?3
?5 and ?8
?6 and ?7
4. Are the angles 1 and 2 given in Fig. 16 adjacent angles?
Solution:
No, because they don’t have common vertex.
5. Find the complement of each of the following angles:
(i) 35
o
(ii) 72
o
(iii) 45
o
(iv) 85
o
Solution:
(i) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 35
o
= 55
o
(ii) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
0
– 72
o
= 18
o
(iii) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 45
o
= 45
o
(iv) The two angles are said to be complementary angles if the sum of those angles is 90
o
Complementary angle for given angle is
90
o
– 85
o
= 5
o
6. Find the supplement of each of the following angles:
(i) 70
o
(ii) 120
o
(iii) 135
o
(iv) 90
o
Solution:
(i) The two angles are said to be supplementary angles if the sum of those angles is 180
o
Therefore supplementary angle for the given angle is
180
o
– 70
o
= 110
o
(ii) The two angles are said to be supplementary angles if the sum of those angles is 180
o
Therefore supplementary angle for the given angle is
180
o
– 120
o
= 60
o
(iii) The two angles are said to be supplementary angles if the sum of those angles is
180
o
Therefore supplementary angle for the given angle is
180
o
– 135
o
= 45
o
(iv) The two angles are said to be supplementary angles if the sum of those angles is
180
o
Therefore supplementary angle for the given angle is
180
o
– 90
o
= 90
o
7. Identify the complementary and supplementary pairs of angles from the following
pairs:
(i) 25
o
, 65
o
(ii) 120
o
, 60
o
(iii) 63
o
, 27
o
(iv) 100
o
, 80
o
Solution:
(i) 25
o
+ 65
o
= 90
o
so, this is a complementary pair of angle.
(ii) 120
o
+ 60
o
= 180
o
so, this is a supplementary pair of angle.
(iii) 63
o
+ 27
o
= 90
o
so, this is a complementary pair of angle.
(iv) 100
o
+ 80
o
= 180
o
so, this is a supplementary pair of angle.
8. Can two obtuse angles be supplementary, if both of them be
(i) Obtuse?
(ii) Right?
(iii) Acute?
Solution:
(i) No, two obtuse angles cannot be supplementary
Because, the sum of two angles is greater than 90
o
so their sum will be greater than
180
o
(ii) Yes, two right angles can be supplementary
Because, 90
o
+ 90
o
= 180
o
(iii) No, two acute angle cannot be supplementary
Because, the sum of two angles is less than 90
o
so their sum will also be less than 90
o
9. Name the four pairs of supplementary angles shown in Fig.17.
Solution:
The two angles are said to be supplementary angles if the sum of those angles is 180
o
The supplementary angles are
?AOC and ?COB
?BOC and ?DOB
?BOD and ?DOA
?AOC and ?DOA
10. In Fig. 18, A, B, C are collinear points and ?DBA = ?EBA.
(i) Name two linear pairs.
(ii) Name two pairs of supplementary angles.
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