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AC = QR (= 5 cm)
This shows that the three sides of one triangle are equal to the three sides of the other
triangle.
From the above three equality relations, it can be easily seen that A ↔ R, B ↔ P and C
↔ Q.
So, we have ∆ABC ≅ ∆RPQ (By SSS congruence rule)

N.B: The order of the letters in the names of congruent triangles displays the
corresponding relationships.
Thus, when you write ∆ABC ≅ ∆RPQ, you would know that
A lies on R, B on P, C on Q, AB along RP , BC along PQ and AC along RQ.

2) SAS Congruence criterion: If under a correspondence, two sides and the angle
included between them of a triangle are equal to two corresponding sides and the angle
included between them of another triangle, then the triangles are congruent.

EXAMPLE:
Given that in ∆ABC, AB = 7 cm, BC = 5 cm, ∠B = 50° and in ∆DEF, DE = 5 cm, EF = 7
cm, ∠E = 50°. Examine whether the given two triangles are congruent or not, by using
SAS congruence rule. If the triangles are congruent, write them in symbolic form.

SOLUTION:
(a)Here, AB = EF ( = 7 cm)
BC = DE ( = 5 cm)
included ∠B = included ∠E ( = 50°).
Also, A ↔ F B ↔ E and C ↔ D.
Therefore, ∆ABC ≅ ∆FED (By SAS congruence rule)