The Isosceles triangle theorem is used to determine if the base angles of a triangle are congruent.
What is base angles of triangle?
"The angles that have the base as one of the side of triangle. "
What is isosceles triangle?
"It is a triangle that has any two sides equal in length and angles opposite to equal sides are equal in measure."
For given question,
We need to find the theorem that is used to determine if the base angles of a triangle are congruent.
We know that the Isosceles triangle theorem states that 'If two sides of a triangle are congruent, then angles opposite those sides are congruent.'
In isosceles triangle any two sides of the triangle are equal in length.
If we draw the angle bisector for an angle between two equal sides, then we get two triangles.
Then by SAS congruence postulates we can prove that both the triangles are congruent and so the base angles of a triangle are congruent.
Therefore, an Isosceles triangle theorem is used to determine if the base angles of a triangle are congruent.
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