Which properties belong to all isosceles triangles? Check all that apply.

An isosceles triangle has two congruent sides, so the sides opposite the two base angles are congruent (C), and the base angles are congruent (A). The symmetry of an isosceles triangle also means the vertex-angle bisector meets the base at a right angle and its midpoint, making it the base’s perpendicular bisector (E). The triangle need not have all three angles or all three sides congruent.

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