AP Board 7th Class Maths Solutions Chapter 4 Lines and Angles Exercise 4.2

SCERT AP 7th Class Maths Solutions Pdf Chapter 4 Lines and Angles Ex 4.2 Textbook Exercise Questions and Answers.

AP State Syllabus 7th Class Maths Solutions 4th Lesson Lines and Angles Exercise 4.2

Question 1.
Observe the given figure and write any 2 linear pairs of angles.
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 1
Answer:
Linear pair of angles :
∠KOQ, ∠QOP
∠KOQ, ∠KOL
∠KOL, ∠LOP
∠QOP, ∠POL
∠KOM, ∠MOP
∠QOM, ∠MOL

Question 2.
Draw a pair of adjacent angles which are complementary to each other.
Answer:
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 2
In the figure ∠AOB, ∠BOC are adjacent angles and their sum is complementary.
∴ ∠AOB + ∠BOC = 50° + 40° = 90°

Question 3.
Draw a pair of adjacent angles which are supplementary to each other.
Answer:
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 3
In the figure ∠POQ, ∠OOR are linear pair and adjacent angles and their sum is supplementary.
∴ ∠POQ + ∠OOR = 110° + 70° = 180°

Question 4.
Give any two examples of adjacent angles in your surroundings.
Answer:
Fan, Bullock cart wheel, Clock, etc.

AP Board 7th Class Maths Solutions Chapter 4 Lines and Angles Exercise 4.2

Question 5.
Observe the figure and write the adjacent angles.
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 4
Answer:
In the given figure, adjacent angles are
∠AOC, ∠COB
∠AOC, ∠COD
∠COD, ∠DOB
∠AOD, ∠DOB

Question 6.
Is it possible for the following pair of angles to form a linear pair? If yes, draw them. If not, give reason.
(i) 120°, 60°
Answer:
Yes.
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 5
120° + 60° = 180°
120°, 60° (Linear pair)

(ii) 98°, 102°
Answer:
No, their sum is not equal to 180°
98° + 102° = 200° > 180°
So, they are not 1irear pair.

Question 7.
Draw the following angles as linear pair. Write the straight line and common arm.
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 6
Answer:
∠BOA + ∠AOC = 180°
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 7
∴ ∠BOA and ∠AOC are linear pair.
BC is a straight line and OA is an arm.

Question 8.
In the given figure, AB is a straight line. O is a point on AB . Find the value of x.
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 8
Answer:
In the given figure \(\overrightarrow{\mathrm{AB}}\) is a straight line.
∠AOC + ∠COB = 180°
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 9
⇒ 2x + 30° + x = 180°
⇒ 3x + 30°= 180°
⇒ 3x + 30° – 30°= 180°
⇒ 3x = 150°
⇒ \(\frac{3 x}{3}=\frac{150^{\circ}}{3}\)
⇒ x = 50

AP Board 7th Class Maths Solutions Chapter 4 Lines and Angles Exercise 4.2

Question 9.
Teacher asked students to check whether 40° and 140° form a linear pair or not by drawing angles. The students have drawn as follows. Who will get correct answer?
AP Board 7th Class Maths Solutions Chapter Chapter 4 Lines and Angles Ex 4.2 10
Answer:
Raheem: ∠AOD = 140°, ∠BOC = 40° they are not adjacent angles and not linear pair.
So, Raheem is not correct.

Mary: ∠COD = 140°, ∠BOC = 40° they are adjacent angles, but they are not linear pair.
So, Mary answer is not correct.

Roshitha: ∠XOZ = 140°, ∠ZOY = 40° they are adjacent angles and linear pair.
So, Roshitha answer is correct.

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