Class 9 Exam  >  Class 9 Notes  >  Mathematics (Maths) Class 9  >  Value-Based Questions: Lines & Angles

Class 7 Maths Chapter 6 Question Answers - Lines and Angles

Question 1. On Monday Prashant’s school bus was late due to a traffic jam and his maths class was missed. He was very upset as his teacher had introduced a new topic on geometry. Rahul promised to help him after school. Rahul went to Prashant’s house and explained the topic. He also gave him the following test also: Which of the following statements are true? 

(a) Two adjacent angles are said to form a linear pair of angles if their uncommon arms are two opposite rays.

(b) The sum of all the angles around a point is equal to 180°. 

(c) The measure of an angle is twice the measure of its supplementary angle. Its measure is 60°. 

(d) The angle between the bisectors of a linear pair of angles is a right angle.

(e) Three or more lines are said to be concurrent if there is a point that lies on all of them.
 (i) Write the appropriate answers to the above questions.
 (ii) Which mathematical concept is used in the above problem?
 (iii) By explaining the topic to Prashant, which value is depicted by Rahul?
 Solution.
(i) The appropriate answers are:
(a) True
(b) False
(c) False
(d) True
(e) True
(ii) Lines and Angles (Geometry).
(iii) Helping a friend in need.

 

Question 2. Three friends plan to help flood victims. They move away from a point in three different directions such that the direction of each is equally inclined to those of the other two:
 (i) Find the angles their directions make with another.
 (ii) Which mathematical concept is used in the above problem?
 (iii) By helping the flood victims, which value is depicted by the teachers and students?
 Solution.
(i) Let ‘O’ be the point from where the three friends move to the points A, B and C, such that OA makes equal angles with OB and OC such that
∠AOB = ∠AOC                       ..... (i)
Also, OB makes equal angles with OA and OC

Class 7 Maths Chapter 6 Question Answers - Lines and Angles

Such that
∠AOB = ∠BOC                   ..... (ii)
From (i) and (ii), we get
∠AOB = ∠BOC = ∠AOC             ..... (iii)
Since the sum of all angles around a point = 360°
⇒ ∠AOB + ∠BOC + ∠AOC = 360°
⇒ ∠AOB + ∠AOB + ∠AOB = 360°               [from iii]
⇒ 3 ∠AOB = 360°
⇒ ∠AOB = (360°/3)= 120°
∴ From (iii), we have: ∠BOC = 120° and ∠AOC = 120°

(ii) Lines and Angles (Geometry)

(iii) Helping attitude towards disastrous victims.

The document Class 7 Maths Chapter 6 Question Answers - Lines and Angles is a part of the Class 9 Course Mathematics (Maths) Class 9.
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FAQs on Class 7 Maths Chapter 6 Question Answers - Lines and Angles

1. What are lines and angles in geometry?
Ans. In geometry, lines are infinitely long straight paths that extend in both directions, while angles are formed when two lines meet at a common point. Lines and angles are fundamental concepts that help describe the relationships and properties of geometric figures.
2. What is the difference between a line segment and a ray?
Ans. A line segment is a part of a line that has two endpoints, while a ray is a part of a line that has one endpoint and extends infinitely in one direction. A line segment has a definite length, whereas a ray has infinite length.
3. How are angles classified based on their measurements?
Ans. Angles can be classified into different types based on their measurements. They are: - Acute angles: Angles that measure less than 90 degrees. - Right angles: Angles that measure exactly 90 degrees. - Obtuse angles: Angles that measure more than 90 degrees but less than 180 degrees. - Straight angles: Angles that measure exactly 180 degrees. - Reflex angles: Angles that measure more than 180 degrees but less than 360 degrees.
4. What are complementary angles?
Ans. Complementary angles are two angles that add up to 90 degrees. In other words, when the measures of two angles sum up to 90 degrees, they are called complementary angles. For example, if one angle measures 30 degrees, the other angle complementary to it will measure 60 degrees.
5. How can we determine if two lines are parallel?
Ans. Two lines are parallel if they never intersect and are always equidistant from each other. One way to determine if two lines are parallel is by comparing their slopes. If the slopes of two lines are equal, they are parallel. Another way is to observe if the corresponding angles formed by a transversal cutting the lines are equal. If the corresponding angles are equal, the lines are parallel.
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