 Hello and welcome to the recession in this session. We will discuss criteria for congruence of triangles We have different criterion to find out the congruency of two triangles like the first one that we discuss is SSS congruence criterion now in this we have if under a given correspondence the three sides of One triangle are equal to the three corresponding sides of another triangle Then the triangles are congruent. So there are these two triangles triangle ABC and triangle PQR as you can see that the side AB of the triangle ABC is of the same measure as The side PQ of the triangle PQR. That is we have AB is equal to PQ BC is equal to QR and AC is equal to PR So we can say by SSS congruence criteria triangle ABC is congruent to the triangle PQR Now, we should also remember one thing that the order of the letters in the names of the congruent triangles Displaced the corresponding relationships. So the orders of the letters should be kept in mind Now next congruence criterion that we have is SAS congruence criterion which says that 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 considering triangle ABC and Triangle PQR in this as you can see that the side AB is equal to the side PQ AC is equal to PR and angle A is equal to angle P So from SAS congruence criterion, you can say that triangle ABC is congruent to the triangle PQR since the two sides and The angle included between them of triangle ABC are equal to the corresponding sides and the angle included between them of the triangle PQR next we have ASA congruence Criterion according to which we have that if under a correspondence two angles and the included side of a triangle are equal to two corresponding angles and the included side of another triangle then the triangles are consider the triangle ABC and triangle PQR in this we have the side AB of triangle ABC is equal to the side PQ of triangle PQR Angle A is equal to angle P Angle B is equal to angle R So by ASA congruence criterion, we say that triangle ABC is congruent to the triangle PQR Whenever we are given two angles and one side of one triangle are equal to the corresponding two angles and one side of another triangle Then we may convert it into two angles and the included side form of congruence and then we can apply ASA congruence rule or the ASA congruence criterion to show the congruence here of the two triangles and This can be done by finding the third angle of the triangle when we are given the two angles of a triangle Next we discuss about the congruence among right angle triangles now the congruence criterion for the right angle Triangles is given as RHS congruence criterion Now in this we have That is under a correspondence the hypotenuse at one side of a right-angled triangle are respectively equal to the hypotenuse and one side of another right-angled triangle Then the triangles are congruent consider ABC Which is right angle that be and triangle PQR which is right angle that Q that is we have Angle B is equal to 90 degrees and angle Q is equal to 90 degrees so angle B is equal to angle Q and Also as you can see that the hypotenuse of the triangle ABC that is AC is equal to the hypotenuse of the triangle PQR which is PR and the side DC of triangle ABC is equal to the side QR of the triangle PQR So by RHS congruence criterion we have triangle ABC is congruent to the triangle PQR So now we have discussed for congruence criterion SSS SAS ASA and RHS Now we should also know one thing that there is no such thing as AAA congruence of two triangles that is two triangles with equal corresponding angles need not be congruent in Such a correspondence one of them can be an enlarged copy of the other So this completes the session Hope you have understood the criteria for congruence of triangles