Triangles Class 10 PPT

 Page 1


Chapter - 7
TRIANGLES
A closed figure formed by three intersecting lines is 
called a triangle .
A triangle has three sides, three angles and three 
vertices.
A
B
C
AB, BC, CA are the three sides, ?A, ?B, ? C are the three 
angles and A, B, C are three vertices.
Page 2


Chapter - 7
TRIANGLES
A closed figure formed by three intersecting lines is 
called a triangle .
A triangle has three sides, three angles and three 
vertices.
A
B
C
AB, BC, CA are the three sides, ?A, ?B, ? C are the three 
angles and A, B, C are three vertices.
Meaning of ‘congruent’
Equal in all respects or figures whose shapes and 
sizes are both the same
congruent figures
Page 3


Chapter - 7
TRIANGLES
A closed figure formed by three intersecting lines is 
called a triangle .
A triangle has three sides, three angles and three 
vertices.
A
B
C
AB, BC, CA are the three sides, ?A, ?B, ? C are the three 
angles and A, B, C are three vertices.
Meaning of ‘congruent’
Equal in all respects or figures whose shapes and 
sizes are both the same
congruent figures
Find congruent figures
Page 4


Chapter - 7
TRIANGLES
A closed figure formed by three intersecting lines is 
called a triangle .
A triangle has three sides, three angles and three 
vertices.
A
B
C
AB, BC, CA are the three sides, ?A, ?B, ? C are the three 
angles and A, B, C are three vertices.
Meaning of ‘congruent’
Equal in all respects or figures whose shapes and 
sizes are both the same
congruent figures
Find congruent figures Symbol of congruence
?
Note that in congruent triangles corresponding parts 
are equal and we write in short ‘CPCT’ for 
corresponding parts of congruent triangles.
Criteria for Congruence of Triangles
Page 5


Chapter - 7
TRIANGLES
A closed figure formed by three intersecting lines is 
called a triangle .
A triangle has three sides, three angles and three 
vertices.
A
B
C
AB, BC, CA are the three sides, ?A, ?B, ? C are the three 
angles and A, B, C are three vertices.
Meaning of ‘congruent’
Equal in all respects or figures whose shapes and 
sizes are both the same
congruent figures
Find congruent figures Symbol of congruence
?
Note that in congruent triangles corresponding parts 
are equal and we write in short ‘CPCT’ for 
corresponding parts of congruent triangles.
Criteria for Congruence of Triangles
1.  SAS congruence rule :-
Two triangles are congruent if two sides and the included 
angle of one triangle are equal to the sides and the 
included angle of the other triangle.