Answer:
Yes
Explanation:
Supplementary means 180 degree.
∠1 + ∠3 = 180 ----> eq. 1
∠2 and ∠3 are linear pair angles which are also supplementary.
∠2 + ∠3 = 180 ----> eq. 2
∠3 = 180 - ∠1 ----> eq. 3
( from eq. 1 )
∠3 = 180 - ∠2 ----> eq. 4
( from eq. 2 )
From, eq. 3 and eq. 4,
180 - ∠1 = 180 - ∠2
Subtract 180 on both sides.
180 - 180 - ∠1 = 180 - 180 - ∠2
- ∠1 = - ∠2
Multiply - 1 on both sides,
∠1 = ∠2
Since,
∠1 = ∠2
Sides opposite to them also equal
So, AC = BC
If any two sides in a triangle is equal, then the triangle is an isosceles triangle.
Therefore,
Δ ABC is isosceles.