NCERT Class 7 Mathematics

140 MATHEMATICS

EXAMPLE 3 In Fig 7.13, AD = CD and AB = CB.

(i) State the three pairs of equal parts in ΔABD and ΔCBD.

(ii) Is ΔABD≅ΔCBD? Why or why not?

(iii) Does BD bisect ∠ABC? Give reasons.

SOLUTION

(i) In ΔABD and ΔCBD, the three pairs of equal parts are as given below:

AB = CB (Given)

AD = CD (Given)

and BD = BD (Common in both)

(ii) From (i) above, ΔABD≅ΔCBD (By SSS congruence rule)

(iii) ∠ABD = ∠CBD (Corresponding parts of congruent triangles)

So, BD bisects ∠ABC.

1. In Fig 7.14, lengths of the sides of the triangles are indicated. By applying the SSS
   congruence rule, state which pairs of triangles are congruent. In case of congruent
   triangles, write the result in symbolic form:

Fig 7.13

TRY THESE

(i)

(ii)

(iii) Fig 7.14 (iv)