**Assertion and Reason Questions for Class 9 Maths Chapter 6 Lines and Angles**

** Directions: **In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

(C) Assertion (A) is true but reason (R) is false.

(d) Assertion (A) is false but reason (R) is true.

**Q.1. Assertion :** Sum of the pair of angles 120Â° and 60Â° is supplementary.**Reason: **Two angles, the sum of whose measures is 180Â°, are called supplementary angles.

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Answer: (a)**Q.2. Assertion:** The angles of a triangle are in the ratio 2:3: 4. The largest angle of the triangle is 80Â°.**Reason: **The sum of all the interior angles of a triangle is 180Â°

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Answer: (a)**Q.3. Assertion : **If angles ‘a’ and ‘b’ form a linear pair of angles and a = 40Â°, then b = 150Â°.**Reason:** Sum of linear pair of angles is always 180Â°.

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Answer: (d)**Q.4. Assertion: **In the given figure, AOB is a straight line. If âˆ AOC = (3x + 10)Â° and âˆ BOC (4x â€“ 26)Â°, then âˆ BOC = 86^{0}**Reason:** The sum of angles that are formed on a straight line is equal to 180Â°

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Answer: (a)**Q.5. Assertion :** If two interior angles on the same side of a transversal intersecting two parallel lines are in the ratio 5:4, then the greater of the two angles is 100^{0}**Reason:** If a transversal intersects two parallel lines, then the sum of the interior angles on the same side of the transversal is 180^{0}

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Answer: (a)**Q.6. Assertion : **An angle is 14Âº more than its complementary angle, then angle is 52Âº.**Reason: **Two angles are said to be supplementary if their sum of measure of angles is 180Â°

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Answer: (b)**Q.7. Assertion : **Supplement of angle is one fourth of itself. The measure of the angle is 144^{0}**Reason: **Two angles are said to be supplementary if their sum of measure of angles is 180^{0}

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Answer: (a)**Q.8. Assertion: **The value of x from the adjoining figure, if â„“ || m is 15Âº.**Reason:** If two parallel lines are intersected by a transversal, then each pair of corresponding angles so formed is equal.

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Answer: (b)**Q.9. Assertion :** If two internal opposite angles of a triangle are equal and external angle is given to be 110Â°, then each of the equal internal angle is 55^{0}.**Reason: **A triangle with one of its angle 90^{0}, is called a right triangle

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Answer: (b)**Q.10. Assertion : **A triangle can have two obtuse angles.**Reason: **The sum of all the interior angles of a triangle is 180Â°

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Answer: (d)**Q.11. Assertion : **The angles of a triangle are in the ration 3:5:7. The triangle is acute-angled**Reason: **The sum of angles that are formed on a straight line is equal to 180Â°.

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Answer: (b)**Frequently Asked Questions (FAQs)**

**What is a line segment?**

A line segment is a part of a line with two end-points.

**What do you mean by perpendicular lines?**

When two lines cut each other at right angle, then lines are called perpendicular lines.Â

**What do you mean by parallel lines?**

Two lines are said to be parallel when they do not meet at any point or which do not intersects each other.

**What is a transversal line?**

When a line intersects two lines at distinct points, it is called a transversal.

**What do you mean by collinear points?**

Collinear points are a set of points (3 or more) which lie on the same line.

**What do you mean by ray?**

A ray is a part of a line, which has a starting point and extendsÂ infinitely in one direction.

**What do you mean by acute angle?**

If the inclination between the arms is less than a right angle, it is called an acute angle.

**What do you mean by obtuse angle?**

If the inclination between the arms is more than a right angle, it is called an obtuse angle.

**What do you mean by right angle?**

If the arms form an angle of 90 degrees between them, it is called a right angle.

**What do you mean by complementary angles?**

Two angles whose sum is equal to 90 degrees are called complementary angles.

**What do you mean by Supplementary Angles?**

Two angles whose sum is equal to 180 degrees are called supplementary angles.

**What do you mean by adjacent angles?**

Two angles which have a common side and a common vertex are called adjacent angles.

**What do you mean by vertically opposite angles?**

Two angles which are formed, opposite to each other, when two lines intersect at a point or vertex, are called vertically opposite angles.