Mathematics Questions and Answers – Lines and Angles Definitions and Basic Terms

This set of Mathematics Multiple Choice Questions & Answers (MCQs) focuses on “Lines and Angles Definitions and Basic Terms”.

1. A line with two endpoints is called __________
a) line
b) ray
c) line-segment
d) triangle
View Answer

Answer: c
Explanation: A line-segment has two endpoints, P and Q as shown in below diagram.

2. How many endpoints does a ray have?
a) One
b) Two
c) Three
d) Four
View Answer

Answer: a
Explanation: A ray has one end point P as shown in below diagram. It originates from this point.

3. If x is an acute angle, then what is true for x?
a) x = 90°
b) 0° < x < 90°
c) 90° < x < 180°
d) 180° < x < 360°
View Answer

Answer: b
Explanation: An acute angle always measures between 0° and 90°, therefore the value of an acute angle is always between 0° and 90°. It is shown in the diagram below in which ∠POQ is an acute angle whose value is less than 90°.

4. If x is an obtuse angle, then what is true for x?
a) x = 90°
b) 180° < x < 360°
c) 0° < x < 90°
d) 90° < x < 180°
View Answer

Answer: d
Explanation: An obtuse angle always measures between 90° and 180°, therefore the value of an acute angle is always between 90° and 180°. In the diagram given below, ∠PQR is an obtuse angle whose value is greater than 90° and less than 180°.

5. If x is a right angle, what is true for x?
a) x = 90°
b) 180° < x < 360°
c) 0° < x < 90°
d) 90° < x < 180°
View Answer

Answer: a
Explanation: A right angle is exactly equal to 90°. It is shown in the diagram below in which ∠POQ is the right angle whose value is equal to 90°.

6. What is the angle formed by a line?
a) 90°
b) 180°
c) 270°
d) 360°
View Answer

Answer: b
Explanation: It can be shown in the diagram given below that angle formed by a line is 180 degree.

7. If 180° < x < 360°, then x is a __________ angle.
a) acute
b) obtuse
c) reflex
d) right
View Answer

Answer: c
Explanation: An angle which is greater than 180° but less than 360° is called reflex angle. It is shown in the diagram below in which ∠PQR is a reflex angle.

8. From the given diagram below, which are the pairs of adjacent angles?

a) ∠PQR and ∠PQS
b) ∠PQR and ∠SQR
c) ∠PQR and ∠RQP
d) ∠PQS and ∠SQR
View Answer

9. From the given diagram below, which pair do angles POR and ROQ form?

a) Linear
b) Adjacent
c) Vertically opposite
d) Supplementary
View Answer

10. The sum of complimentary angles is __________
a) > 90°
b) < 90°
c) = 90°
d) = 180°
View Answer

Answer: c
Explanation: When the sum of two angles are equal to 90°, they are called complimentary angles. In the diagram shown below, ∠POR and ∠ROQ are complimentary angles because ∠POR + ∠ROQ = 90°.

11. The sum of two supplementary angles is __________
a) > 90°
b) < 90°
c) = 90°
d) = 180°
View Answer

Answer: d
Explanation: When the sum of two angles are equal to 180°, they are called supplementary angles. In the diagram shown below, ∠POR and ∠ROQ are supplementary angles because ∠POR + ∠ROQ = 180°.

Sanfoundry Global Education & Learning Series – Mathematics – Class 9.

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