|Class 7 Maths Congruence of Triangles||Congruence of Angles|
Congruence of Angles
If two angles have the same measure, they are congruent. Also, if two angles are congruent, their measures are same.
In the above figure (i) and (ii), place Q on B and QP along AB. So, ∠PQR matches exactly ∠ABC.
Thus ∠ABC and ∠PQR are congruent.
=> ∠ABC ≅ ∠PQR
=> m∠ABC = m∠PQR [Since each angle is 400]
Again, in the above figure (i) and (iii), ∠LMR do not matches with ∠ABC.
Thus ∠ABC and ∠LMR are not congruent.
Again take figure (i) and (iv), they are congruent to each other because ∠XYZ matches exactly ∠ABC.
=> ∠ABC ≅ ∠XYZ
=> m∠ABC = m∠XYZ [Since each angle is 400]