AP State Syllabus AP Board 9th Class Maths Solutions Chapter 4 Lines and Angles Ex 4.1 Textbook Questions and Answers.

## AP State Syllabus 9th Class Maths Solutions 4th Lesson Lines and Angles Exercise 4.1

Question 1.

In the given figure, name:

i) Any six points

Solution:

A, B, C, D, P, Q, M, N etc.

ii) Any five line segments

Solution:

\(\overline{\mathrm{AX}}, \overline{\mathrm{XM}}, \overline{\mathrm{MP}}, \overline{\mathrm{PB}}, \overline{\mathrm{MN}}, \overline{\mathrm{PQ}}, \overline{\mathrm{AB}} \ldots \ldots\) etc.

iii) Any four rays

Solution:

\(\overline{\mathrm{MA}}, \overline{\mathrm{PA}}, \overline{\mathrm{PB}}, \overline{\mathrm{NC}}, \overline{\mathrm{QD}} \ldots \ldots\) etc.

iv) Any four lines

Solution:

\(\overline{\mathrm{MA}}, \overline{\mathrm{PA}}, \overline{\mathrm{PB}}, \overline{\mathrm{NC}}, \overline{\mathrm{QD}} \ldots \ldots\)

v) Any four collinear points

Solution:

A, X, M, P and B are collinear points on the line \(\overline{\mathrm{AB}}\).

Question 2.

Observe the following figures and identify the type of angles in them.

Solution:

∠A – reflex angle

∠B – right angle

∠C – acute angle

Question 3.

State whether the following state¬ments are true or false

i) A ray has no end point.

ii) Line \(\overline{\mathrm{AB}}\) is the same as line \(\overline{\mathrm{BA}}\)

iii) A ray \(\overline{\mathrm{AB}}\) is same as the ray \(\overline{\mathrm{BA}}\)

iv) A line has a definite length.

v) A plane, has length and breadth but no thickness.

vii) Two lines may intersect in two points.

viii) Two intersecting lines cannot both be parallel to the same line.

Solution:

i) A ray has no end point. – False

ii) Line \(\overline{\mathrm{AB}}\) is the same as line \(\overline{\mathrm{BA}}\) – True

iii) A ray \(\overline{\mathrm{AB}}\) is same as the ray \(\overline{\mathrm{BA}}\) – False

iv) A line has a definite length. – False

v) A plane, has length and breadth but no thickness. – True

vi) Two distinct points always determine a unique line. – True

vii) Two lines may intersect in two points. – False

viii) Two intersecting lines cannot both be parallel to the same line. – True

Question 4.

What is the angle between two hands of a clock when the lime in the clock

is

a) 9 ‘o clock

b) 6 ‘o clock

c) 7 ; 00 p.m.

Solution:

a) 12 hours = = 360°

1 hour = \(\frac{360^{\circ}}{12}\) = 30°

∴Angle between hands when the time is 9 o clock = 3 x 30 = 90

b)

Angle between hands = 6 x 30° = 180°

c)

Angle between hands = 7 x 30° = 210°