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°