CBSE Class 7 Maths Chapter 7: A Tale of Three Intersecting Lines — Assertion & Reason
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The following Assertion and Reason questions are based on Chapter 7: A Tale of Three Intersecting Lines from the NCERT Class 7 Mathematics textbook. Each question has four options - read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): A triangle has three sides and three vertices.
Reason (R): It is formed by joining three non-collinear points with segments.
Reason (R): It is formed by joining three non-collinear points with segments.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Non-collinearity creates a closed triangular region.
2
Assertion (A): An equilateral triangle has all three sides equal.
Reason (R): Its three angles are each 60 degrees.
Reason (R): Its three angles are each 60 degrees.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. Both are true, but the angle fact does not define its side equality.
3
Assertion (A): Side lengths 2, 3 and 6 cannot form a triangle.
Reason (R): Their two smaller sides add to more than 6.
Reason (R): Their two smaller sides add to more than 6.
Answer: (c)
A is true, but R is false. They add to 5, so the triangle inequality fails.
4
Assertion (A): Any three positive lengths form a triangle.
Reason (R): They must satisfy the triangle inequalities.
Reason (R): They must satisfy the triangle inequalities.
Answer: (d)
A is false, but R is true. Positive lengths alone are insufficient.
5
Assertion (A): SSS construction determines a triangle when three valid side lengths are given.
Reason (R): Intersections of arcs locate the third vertex at the required distances.
Reason (R): Intersections of arcs locate the third vertex at the required distances.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The compass constraints fix the possible vertex.
6
Assertion (A): A triangle with fixed three sides is unique up to reflection.
Reason (R): Congruent copies can be placed in different orientations.
Reason (R): Congruent copies can be placed in different orientations.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. Both are true, but orientation freedom does not explain the SSS condition.
7
Assertion (A): Two sides and an unspecified angle do not always determine a unique triangle.
Reason (R): The angle's position never matters.
Reason (R): The angle's position never matters.
Answer: (c)
A is true, but R is false. The included or non-included position changes the construction.
8
Assertion (A): A compass is used only to measure angles.
Reason (R): It draws arcs and transfers lengths in constructions.
Reason (R): It draws arcs and transfers lengths in constructions.
Answer: (d)
A is false, but R is true. A protractor measures angles.
9
Assertion (A): An altitude of a triangle is perpendicular from a vertex to the opposite side's line.
Reason (R): The right angle gives the shortest distance to that line.
Reason (R): The right angle gives the shortest distance to that line.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Perpendicularity defines the altitude.
10
Assertion (A): A triangle has three altitudes.
Reason (R): An obtuse triangle can have altitudes outside the triangle.
Reason (R): An obtuse triangle can have altitudes outside the triangle.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. Both are true, but the second does not explain the count.
11
Assertion (A): Some altitudes of an obtuse triangle lie outside it.
Reason (R): All altitudes of every triangle lie inside.
Reason (R): All altitudes of every triangle lie inside.
Answer: (c)
A is true, but R is false. Two altitudes meet extensions of sides.
12
Assertion (A): An altitude must always bisect the opposite side.
Reason (R): A median, not a general altitude, bisects the opposite side.
Reason (R): A median, not a general altitude, bisects the opposite side.
Answer: (d)
A is false, but R is true. Only special triangles make one segment both.
13
Assertion (A): An acute triangle has all angles less than 90 degrees.
Reason (R): Angle classification is based on the triangle's largest angle.
Reason (R): Angle classification is based on the triangle's largest angle.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. If the largest is acute, all are acute.
14
Assertion (A): A right triangle has one 90-degree angle.
Reason (R): An obtuse triangle has one angle greater than 90 degrees.
Reason (R): An obtuse triangle has one angle greater than 90 degrees.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. Both are true definitions, but the second does not explain the first.
15
Assertion (A): A triangle cannot have two obtuse angles.
Reason (R): Two obtuse angles can have a sum below 180 degrees.
Reason (R): Two obtuse angles can have a sum below 180 degrees.
Answer: (c)
A is true, but R is false. Their sum already exceeds 180 degrees.
16
Assertion (A): An equilateral triangle can be right-angled.
Reason (R): All its angles are 60 degrees.
Reason (R): All its angles are 60 degrees.
Answer: (d)
A is false, but R is true. It is acute.
17
Assertion (A): An isosceles triangle has at least two equal sides.
Reason (R): Angles opposite equal sides are equal.
Reason (R): Angles opposite equal sides are equal.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The symmetry of equal sides yields equal base angles.
18
Assertion (A): A scalene triangle has no equal sides.
Reason (R): It may still be acute, right or obtuse.
Reason (R): It may still be acute, right or obtuse.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. Both are true, but angle type does not explain side classification.
19
Assertion (A): Not every isosceles triangle is equilateral.
Reason (R): An isosceles triangle must have all three sides equal.
Reason (R): An isosceles triangle must have all three sides equal.
Answer: (c)
A is true, but R is false. It may have exactly two equal sides.
20
Assertion (A): A triangle's exterior angle is smaller than both remote interior angles.
Reason (R): It equals the sum of the two remote interior angles.
Reason (R): It equals the sum of the two remote interior angles.
Answer: (d)
A is false, but R is true. The sum is greater than either positive part.
❓ Frequently Asked Questions
What is covered in CBSE Class 7 Maths Chapter 7 A Tale of Three Intersecting Lines?
This chapter covers all key topics from A Tale of Three Intersecting Lines as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 7 board exam preparation covering the complete syllabus.
Are these CBSE Class 7 Maths Assertion & Reason updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 7 Maths?
All chapters of CBSE Class 7 Maths are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study A Tale of Three Intersecting Lines online for free?
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