Page 1
Exercise 11.1 page: 11.5
1. Give three examples of angles from your environment.
Solution:
The three examples of angles are
The angle formed by the two adjacent fingers of our hand
The angle formed by two adjacent walls of a room
The angle formed by the hour hand and minute hand of a clock.
2. Write the arms and the vertex of ? LMP given in Fig. 11.14.
Solution:
The vertex of ? LMP is M and the arms are ML and MP.
3. How many angles are formed in the figures 11.15 (i), (ii) and (iii)? Name them.
Solution:
(i) Three angles are formed in figure (i) namely ? ABC, ? ACB and ? BAC.
(ii) Four angles are formed in figure (ii) namely ? ABC, ? BCD, ? CDA and ? DAB.
(iii) Eight angles are formed in figure (iii) namely ? ABC, ? BCD, ? CDA, ? DAB, ? CAB, ? CAD, ? BCA and
? ACD.
4. In Fig. 11.16, list the points which are: (i) in the interior of ? P (ii) in the exterior of ? P and (iii) lie on ?
P.
Page 2
Exercise 11.1 page: 11.5
1. Give three examples of angles from your environment.
Solution:
The three examples of angles are
The angle formed by the two adjacent fingers of our hand
The angle formed by two adjacent walls of a room
The angle formed by the hour hand and minute hand of a clock.
2. Write the arms and the vertex of ? LMP given in Fig. 11.14.
Solution:
The vertex of ? LMP is M and the arms are ML and MP.
3. How many angles are formed in the figures 11.15 (i), (ii) and (iii)? Name them.
Solution:
(i) Three angles are formed in figure (i) namely ? ABC, ? ACB and ? BAC.
(ii) Four angles are formed in figure (ii) namely ? ABC, ? BCD, ? CDA and ? DAB.
(iii) Eight angles are formed in figure (iii) namely ? ABC, ? BCD, ? CDA, ? DAB, ? CAB, ? CAD, ? BCA and
? ACD.
4. In Fig. 11.16, list the points which are: (i) in the interior of ? P (ii) in the exterior of ? P and (iii) lie on ?
P.
Solution:
(i) The points which are in the interior of ? P are J and C.
(ii) The points which are in the exterior of ? P are B and D.
(iii) The points which lie on ? P are A, P and M.
5. In Fig. 11.17, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
(iv) ? 4
Solution:
(i) From the figure, another name for ? 1 is ? BOD or ? DOB.
(ii) From the figure, another name for ? 2 is ? BOC or ? COB.
(iii) From the figure, another name for ? 3 is ? COA or ? AOC.
(iv) From the figure, another name for ? 4 is ? AOD or ? DOA.
6. In Fig. 11.18, write another name for:
Page 3
Exercise 11.1 page: 11.5
1. Give three examples of angles from your environment.
Solution:
The three examples of angles are
The angle formed by the two adjacent fingers of our hand
The angle formed by two adjacent walls of a room
The angle formed by the hour hand and minute hand of a clock.
2. Write the arms and the vertex of ? LMP given in Fig. 11.14.
Solution:
The vertex of ? LMP is M and the arms are ML and MP.
3. How many angles are formed in the figures 11.15 (i), (ii) and (iii)? Name them.
Solution:
(i) Three angles are formed in figure (i) namely ? ABC, ? ACB and ? BAC.
(ii) Four angles are formed in figure (ii) namely ? ABC, ? BCD, ? CDA and ? DAB.
(iii) Eight angles are formed in figure (iii) namely ? ABC, ? BCD, ? CDA, ? DAB, ? CAB, ? CAD, ? BCA and
? ACD.
4. In Fig. 11.16, list the points which are: (i) in the interior of ? P (ii) in the exterior of ? P and (iii) lie on ?
P.
Solution:
(i) The points which are in the interior of ? P are J and C.
(ii) The points which are in the exterior of ? P are B and D.
(iii) The points which lie on ? P are A, P and M.
5. In Fig. 11.17, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
(iv) ? 4
Solution:
(i) From the figure, another name for ? 1 is ? BOD or ? DOB.
(ii) From the figure, another name for ? 2 is ? BOC or ? COB.
(iii) From the figure, another name for ? 3 is ? COA or ? AOC.
(iv) From the figure, another name for ? 4 is ? AOD or ? DOA.
6. In Fig. 11.18, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
Solution:
(i) From the figure, another name for ? 1 is ? EPB or ? BPE.
(ii) From the figure, another name for ? 2 is ? CQP or ? PQC.
(iii) From the figure, another name for ? 3 is ? DQF or ? FQD.
7. In Fig. 11.19, which of the following statements are true:
(i) Point B is the interior of ? AOB.
(ii) Point B is the interior of ? AOC.
(iii) Point A is the interior of ? AOD.
(iv) Point C is the exterior of ? AOB.
(v) Point D is the exterior of ? AOC.
Solution:
(i) False. B lies on ? AOB.
(ii) True
(iii) False. A lies on ? AOD.
(iv) True
(v) True
8. Which of the following statements are true:
(i) The vertex of an angle lies in its interior.
(ii) The vertex of an angle lies in its exterior.
Page 4
Exercise 11.1 page: 11.5
1. Give three examples of angles from your environment.
Solution:
The three examples of angles are
The angle formed by the two adjacent fingers of our hand
The angle formed by two adjacent walls of a room
The angle formed by the hour hand and minute hand of a clock.
2. Write the arms and the vertex of ? LMP given in Fig. 11.14.
Solution:
The vertex of ? LMP is M and the arms are ML and MP.
3. How many angles are formed in the figures 11.15 (i), (ii) and (iii)? Name them.
Solution:
(i) Three angles are formed in figure (i) namely ? ABC, ? ACB and ? BAC.
(ii) Four angles are formed in figure (ii) namely ? ABC, ? BCD, ? CDA and ? DAB.
(iii) Eight angles are formed in figure (iii) namely ? ABC, ? BCD, ? CDA, ? DAB, ? CAB, ? CAD, ? BCA and
? ACD.
4. In Fig. 11.16, list the points which are: (i) in the interior of ? P (ii) in the exterior of ? P and (iii) lie on ?
P.
Solution:
(i) The points which are in the interior of ? P are J and C.
(ii) The points which are in the exterior of ? P are B and D.
(iii) The points which lie on ? P are A, P and M.
5. In Fig. 11.17, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
(iv) ? 4
Solution:
(i) From the figure, another name for ? 1 is ? BOD or ? DOB.
(ii) From the figure, another name for ? 2 is ? BOC or ? COB.
(iii) From the figure, another name for ? 3 is ? COA or ? AOC.
(iv) From the figure, another name for ? 4 is ? AOD or ? DOA.
6. In Fig. 11.18, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
Solution:
(i) From the figure, another name for ? 1 is ? EPB or ? BPE.
(ii) From the figure, another name for ? 2 is ? CQP or ? PQC.
(iii) From the figure, another name for ? 3 is ? DQF or ? FQD.
7. In Fig. 11.19, which of the following statements are true:
(i) Point B is the interior of ? AOB.
(ii) Point B is the interior of ? AOC.
(iii) Point A is the interior of ? AOD.
(iv) Point C is the exterior of ? AOB.
(v) Point D is the exterior of ? AOC.
Solution:
(i) False. B lies on ? AOB.
(ii) True
(iii) False. A lies on ? AOD.
(iv) True
(v) True
8. Which of the following statements are true:
(i) The vertex of an angle lies in its interior.
(ii) The vertex of an angle lies in its exterior.
(iii) The vertex of an angle lies on it.
Solution:
(i) False.
(ii) False.
(iii) True.
9. By simply looking at the pair of angles given in Fig. 11.20, state which of the angles in each of the pairs is
greater:
Solution:
(i) From the figure we know that ? AOB > ? DEF.
(ii) From the figure we know that ? PQR > ? LMN.
(iii) From the figure we know that ? UVW > ? XYZ.
10. By using tracing paper compare the angles in each of the pairs given in Fig. 11.21.
Page 5
Exercise 11.1 page: 11.5
1. Give three examples of angles from your environment.
Solution:
The three examples of angles are
The angle formed by the two adjacent fingers of our hand
The angle formed by two adjacent walls of a room
The angle formed by the hour hand and minute hand of a clock.
2. Write the arms and the vertex of ? LMP given in Fig. 11.14.
Solution:
The vertex of ? LMP is M and the arms are ML and MP.
3. How many angles are formed in the figures 11.15 (i), (ii) and (iii)? Name them.
Solution:
(i) Three angles are formed in figure (i) namely ? ABC, ? ACB and ? BAC.
(ii) Four angles are formed in figure (ii) namely ? ABC, ? BCD, ? CDA and ? DAB.
(iii) Eight angles are formed in figure (iii) namely ? ABC, ? BCD, ? CDA, ? DAB, ? CAB, ? CAD, ? BCA and
? ACD.
4. In Fig. 11.16, list the points which are: (i) in the interior of ? P (ii) in the exterior of ? P and (iii) lie on ?
P.
Solution:
(i) The points which are in the interior of ? P are J and C.
(ii) The points which are in the exterior of ? P are B and D.
(iii) The points which lie on ? P are A, P and M.
5. In Fig. 11.17, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
(iv) ? 4
Solution:
(i) From the figure, another name for ? 1 is ? BOD or ? DOB.
(ii) From the figure, another name for ? 2 is ? BOC or ? COB.
(iii) From the figure, another name for ? 3 is ? COA or ? AOC.
(iv) From the figure, another name for ? 4 is ? AOD or ? DOA.
6. In Fig. 11.18, write another name for:
(i) ? 1
(ii) ? 2
(iii) ? 3
Solution:
(i) From the figure, another name for ? 1 is ? EPB or ? BPE.
(ii) From the figure, another name for ? 2 is ? CQP or ? PQC.
(iii) From the figure, another name for ? 3 is ? DQF or ? FQD.
7. In Fig. 11.19, which of the following statements are true:
(i) Point B is the interior of ? AOB.
(ii) Point B is the interior of ? AOC.
(iii) Point A is the interior of ? AOD.
(iv) Point C is the exterior of ? AOB.
(v) Point D is the exterior of ? AOC.
Solution:
(i) False. B lies on ? AOB.
(ii) True
(iii) False. A lies on ? AOD.
(iv) True
(v) True
8. Which of the following statements are true:
(i) The vertex of an angle lies in its interior.
(ii) The vertex of an angle lies in its exterior.
(iii) The vertex of an angle lies on it.
Solution:
(i) False.
(ii) False.
(iii) True.
9. By simply looking at the pair of angles given in Fig. 11.20, state which of the angles in each of the pairs is
greater:
Solution:
(i) From the figure we know that ? AOB > ? DEF.
(ii) From the figure we know that ? PQR > ? LMN.
(iii) From the figure we know that ? UVW > ? XYZ.
10. By using tracing paper compare the angles in each of the pairs given in Fig. 11.21.
Solution:
(i) From the figure we know that ? PQR > ? AOB.
(ii) From the figure we know that ? UVW > ? LMN.
(iii) From the figure we know that ? RST > ? XYZ.
(iv) From the figure we know that ? PQR > ? EFG.
Read More