Class 7 Maths Chapter 7 Congruence Of Triangle Exercise 7.1 pdf notes:-
Exercise 7.1 Class 7 maths Chapter 7 Pdf Notes:-
Ncert Solution for Class 7 Maths Chapter 7 Congruence Of Triangle Exercise 7.1 Tips:
You are now ready to learn a very important geometrical idea, Congruence. In particular,
you will study a lot about congruence of triangles.
The relation of two objects being congruent is called congruence. For the present,
we will deal with plane figures only, although congruence is a general idea applicable to
three-dimensional shapes also. We will try to learn a precise meaning of the congruence
of plane figures already known.
You can use the method of superposition. Take a trace-copy of one of them and place
it over the other. If the figures cover each other completely, they are congruent. Alternatively,
you may cut out one of them and place it over the other. Beware! You are not allowed to
bend, twist or stretch the figure that is cut out (or traced out).
CONGRUENCE AMONG LINE SEGMENTS
When are two line segments congruent? Observe the two pairs of line segments given
hereUse the ‘trace-copy’ superposition method for the pair of line segments in
Copy CDand place it on AB. You find that CD covers AB, with C on A and D on B.
Hence, the line segments are congruent. We write AB CD ≅ .
Repeat this activity for the pair of line segments in . What do you find?
They are not congruent. How do you know it? It is because the line segments do not
coincide when placed one over other.