Page 1 : ne Segment, of a line is called a tine segment, it has teo fixed eodpoints So. It has, length, segment is the shortest distance between two points, segment AB is written as AB., sides of a triangle, rectangle, square and other plane figures are, ments., Curved Line, es that are not straight and have a bend in them are called curved lines, ey can be drawn as free hand drawings., Exercise 4.1, Match the figures with their names., D], ) Line segment, b) P, i) Line, Hii) Point, iv) Curved line, B, v) Ray, Name all the line segments in each figure., c) A, b), D., AEID.CD.SC RE

Page 2 : 3. Draw a line segment named XY., 4. Draw a vertical line and name it., 5. Draw a ray XY., Intersecting Lines, When two rays, lines or line segments meet at a poin, intersecting lines., The point at which they meet is called the point of inte, in the figures below)., A, D, P., Intersecting lines, Inters, When a horizontal ray, line or line segment meets, segment, they are called perpendicular lines., Two rays, lines or line segments that can never meet, C, A, A -, D, Perpendicular lines, MEASURING LINE SEGMENTS, We usually measure the length of a line segment usir, Let us measure the length of MN.

Page 3 : Exercise 4.2, Measure the length of the following line segments., 3.8, 1., cm, a), 4.9, cm, b), cm, c), cm, d), 2. Draw line segments of the given lengths.Do il, a) 8 cm, b) 7 cm, c) 4 cm, d) 3 cm, e) 9 cm, f) 6 cm, 3., Measure the length of the following., a) notebook, b) a textbook, c) a mobile phone d) a shar, 4., Give real-life examples of parallel lines, intersecting lines and p, lines., ANGLES, Mark a point O in your notebook., Vertex, Draw a ray OA from point O., Draw another ray OB from point O., The rays OA and OB start from the same point O., A, Vhen two rays, lines or line segments meet at a, What is a, in a camer, do? What, does it tal, ommon point, an angle is formed., he two rays OA and OB are called the arms of the, ngle., he point O at which the two rays meet is known as the vertex of, ngle is shown by the symbol Z followed by three letters., h angle is named by writing the vertex at the centre., us, in angle ZAOB, O is the vertex. This angle can also be writte, Pacher's Tip, ke the students to the playground. Help them observe different angles hidden in swings, t, ing tracks and so on.

Page 4 : Move along the curved edge starting from, the mark A. Read the mark on the outer, scale through which the arm OB passes., ep 2:, Remember, When, arm, noides, the, read the, manengson he inner, When the bese arm, cof the une, iricides, The arm OB passes through mark 45°., with the zoto of the, outer scale, read the, markings on the outer, So, the measure of ZAOB is 45°., scale., Thus.AOB = 45°, Exercise 4.4, Measure the given angles using a protractor., 1., 2. P, R., 5., 6., K, P., Types of Angles, Angles are classified according to their measures., Acute angle, An angle whose measure is less than 90° is called an acute, 65, engle. As ZXYZ = 65°, it is an acute angle., %D