CBSE Class 9 Maths Exam 2020-21: Extra Questions (With Answers) - Chapter 5 Introduction To Euclid's Geometry

CBSE: Check important extra questions for the upcoming CBSE Class 9 Maths exam 2020-21 from Chapter 5 Introduction To Euclid's Geometry of Class 9 Maths NCERT textbook. Answers of all the questions are also available here. The time duration to attempt these questions is 5 minutes. Students with sound knowledge of basic concepts of this chapter can easily attempt these questions in one go. These questions might be also asked in CBSE School examinations with slight modification. 

CBSE Class 9 Maths Exam 2020-21: NCERT Based Important Extra Questions (With Answers) Chapter 5 -Introduction To Euclid's Geometry

Question: Fill in the blanks

Axioms are assumed _________.

Answer: 

Axioms are assumed universal truths in all branches of mathematics.

NCERT Solutions for Class 9 - Maths, Science, Social Science and English (Chapter-Wise PDF)

Question: What is Euclid’s fifth postulate?

Answer: 

If a straight line falling on two straight lines makes the interior angles on the same side of it taken together less than two right angles, then the two straight lines if produced indefinitely, meet on that side on which the sum of angles is less than two right angles.

Question: Mohan and Sohan have the same weight. If they each gain weight by 2 kg, how will their new weights be compared ?

Answer: 

Let x kg be the weight each of Mohan and Sohan. On gaining 2 kg, the weight of Mohan and Sohan will be (x + 2) each. According to Euclid’s second axiom, when equals are added to equals, the wholes are equal. So, the weight of Mohan and Sohan are again equal.

Question: Solve the equation x – 25 = 25 and state which axiom do you use here. 

Solution: x – 25 = 25. On adding 25 to both sides, we have x – 25 + 25 = 25 + 25 = 50 (using Euclid’s second axiom) or x = 50.

Question:How many numbers of dimensions do a solid have?

Answer:

Three.

Question: How many numbers of dimensions do a surface have?

Answer:

Two.

Question: How many numbers of dimensions do a point have?

Answer:

Zero.

Question: It is known that if a + b = 10 then a + b + c = 10 + c. The Euclid’s axiom that illustrates this statement is :

(A) 1st Axiom 

(B) 2nd Axiom

(C) 3rd Axiom 

(D) 4th Axiom

Answer:

(B)

Question: Fill in the blanks:

The Euclidean geometry is valid only for figures in the _______

Answer: Plane

The Euclidean geometry is valid only for figures in the plane. It fails on the curved surfaces. For example on curved surfaces, the sum of angles of a triangle may be more than 180°.

Question: Euclid’s fourth axiom says that _____________

Answer:

Euclid’s fourth axiom says that _____everything equals itself_____.

It is the justification of the principle of superposition

CBSE Class 9 Science Important Questions & Answers for Annual Exam 2020