Congruence in Grade VII

Hello friends, in grade VI we get basic idea and geometry help according to grade VI, but in grade VII of Gujarat Board Syllabus we will  have to learn new concept of geometry and learn solving equations based on it. So, in today's session we all are going to discuss about one of the most interesting topic of geometry which is congruence.
Two objects are said to be congruent, if one object is the exact copy of another object means both objects have same shape and shape size like two  photocopied papers are called as a Congruent because both have same size and same shape and relation of two objects being congruent is  called a congruence. So, first of all we will discuss concept of congruence  :
Congruence of plane figures: if one plane figure matches with another figure then this relation is called as Congruence between plane figures  like

if we put one figure onto another figure, it completely covers the other and when two figures completely covers each other then relation between these two plane figures are called as a Congruence of plane figures.(want to Learn more about Congruence,click here),
Congruence between lines: If two lines are equal means both lines have same length then both lines are called as a congruent lines. For understanding congruence between lines, we take two lines AB and CD

if we put CD on AB and it covers AB completely means C covers A and D covers B then CD and AB called as a congruent and relationship  between these two lines are called as a congruence between these two lines.
Congruence of angles: when angle between two line segments are same then this relationship between two angles is called as a congruence of  angles. For understanding congruence of angles, we take an example

here both angles A and B are same. These two angles are known as congruent angles.
Congruence of triangles: There are some rules which define Congruence of triangles

• side-angle-side rule : when two sides and one angle of triangle is equal to another triangle then both triangles are known as a congruent triangles. like. The figure below shows this.

Here two sides are 4cm and 5cm and one angle 100 degree are equal to other triangle. So both triangles are known as a congruent triangles.

• angle-side-angle rule : when two angles and one side of triangle is equal to other triangle then both triangles are known as a congruent  triangles as shown in the image below

       
here two angles 75 degree and 65 degree and one side 10cm are equal to other triangle, then both triangles are known as congruent triangles.

• side-side-side rule : if all three side of one triangle is equal to all side of other triangle then both triangles are said to be congruent  triangles as shown in the image below

Here all three sides are equal to each that's why both triangles are known as a congruent triangles.

• angle-angle-angle rule: if all angles of one triangle is equal to all angles of other triangle then both triangles are said to be congruent triangles.

Here all angles are same in both triangles so both triangles are known as congruent triangles.
This is all about rules to prove congruence between triangles and if anyone want to know about Eighth grade quadratic equations then they can refer to Internet and text books for understanding it more precisely. You can also refer Grade VII blog for further reading on Measurements in Mathematical World.
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