SHOW THAT THE ANGLES OPPOSITE TO EQUAL SIDES OF A TRIANGLE ARE EQUAL
Answers
Step-by-step explanation:
Theorem : Angles opposite to equal sides of an isosceles triangle are equal.
This result can be proved in many ways. One of the proofs is given here.
Proof :
We are given an isosceles triangle ABC in which AB = AC. We need to prove that ∠B = ∠C.
Let us draw the bisector of ∠ A and let D be the point of intersection of this bisector of ∠ A and BC.
In Δ BAD and Δ CAD,
AB = AC (Given)
∠BAD = ∠CAD (By construction)
AD = AD (Common)
So, Δ BAD ≅ Δ CAD (By SAS rule)
So, ∠ABD = ∠ACD, since they are corresponding angles of congruent triangles.
So, ∠B = ∠C
U can try this experiment too !!!
Construct a triangle ABC with BC of any length and ∠ B = ∠ C = 50°. Draw the bisector of ∠ A and let it intersect BC at D .Cut out the triangle from the sheet of paper and fold it along AD so that vertex C falls on vertex B.What can you say about sides AC and AB? Observe that AC covers AB completely So, AC = AB