NCERT Class 7 Mathematics

LINES AND ANGLES 99 Observe a vegetable chopping board (Fig 5.12). A vegetable chopping board A pen stand The chopping blade mak ...

100 MATHEMATICS 5.2.5 Vertically Opposite Angles Next take two pencils and tie them with the help of a rubber band at the middle ...

LINES AND ANGLES 101 We conclude that when two lines intersect, the vertically opposite angles so formed are equal. Let us try t ...

102 MATHEMATICS Find the supplement of each of the following angles: (i) (ii) (iii) Identify which of the following pairs of ...

LINES AND ANGLES 103 In the following figure, is ∠1 adjacent to ∠2? Give reasons. Find the values of the angles x,y, and z in e ...

104 MATHEMATICS The blackboard on its stand, the letter Y made up of line segments and the grill-door of a window (Fig 5.19), wh ...

LINES AND ANGLES 105 In the Fig 5.22, p is a transversal to the lines l and m. Fig 5.22 Fig 5.23 In Fig 5.23 the line p is not a ...

106 MATHEMATICS (iii) are in ‘corresponding’ positions (above or below, left or right) relative to the two lines. Fig 5.25 Alter ...

LINES AND ANGLES 107 Take a ruled sheet of paper. Draw (in thick colour) two parallel lines l and m. Draw a transversal t to the ...

108 MATHEMATICS You can similarly show that ∠1 = ∠6. Thus, we have the following result : If two parallel lines are cut by a tra ...

LINES AND ANGLES 109 Linesl||m; Lines a||b; l 1 ,l 2 be two lines t is a transversal c is a transversal t is a transversal ∠ x ...

110 MATHEMATICS Draw a line l (Fig 5.32). Draw a line m, perpendicular to l. Again draw a line p, such that p is perpendicular t ...

LINES AND ANGLES 111 Find the value of x in each of the following figures if l || m. (i) (ii) (iii) In the given figure, the ...

112 MATHEMATICS (i) When two lines intersect (looking like the letter X) we have two pairs of opposite angles. They are called ...

6.1 INTRODUCTION A triangle, you have seen, is a simple closed curve made of three line segments. It has three vertices, three s ...

114 MATHEMATICS Fig 6.2 Now, let us try to explore something more about triangles. 6.2 MEDIANS OF A TRIANGLE Given a line segmen ...

THE TRIANGLE AND ITS PROPERTIES 115 6.3 ALTITUDES OF A TRIANGLE Make a triangular shaped cardboard ABC. Place it upright, on a t ...

116 MATHEMATICS EXERCISE 6.1 InΔ PQR, D is the mid-point of QR. PM is _________________. PD is _________________. Is QM MR? D ...

THE TRIANGLE AND ITS PROPERTIES 117 You may repeat the above two activities by drawing some more triangles along with their exte ...

118 MATHEMATICS EXAMPLE 1 Find angle x in Fig 6.11. SOLUTION Sum of interior opposite angles Exterior angle or 50° + x 110° or x ...