Answer:
AAS(Angle-Angle-Side) postulate states that if two angles and the non-included side one triangle are congruent to two angles and the non-included side of another triangle, then the two triangles are congruent
In triangle RAS and triangle QAT
[Angle]
[Side] [Given]
By Base Angle Theorem states that in an isosceles triangle(i.e, AST), the angles opposite the congruent sides(AS =AT) are congruent.
⇒ [By base ∠'s of isosceles triangle are equal]
By definition of supplementary angles, if two Angles are Supplementary when they add up to 180 degrees.
,
are supplementary and
,
are supplementary.
⇒ and
Two supplementary to equal
Since,
then, we get;
[Angle]
then, by AAS postulates,
By CPCT[Corresponding Part of Congruent Triangles are equal]
Hence Proved!
