Triangle XYZ is isoceles. The measure of the vertex angle, cap y , is twice the measure of a base angle. What is true about triangle XYZ ? Choose three correct answers.

The two base angles are equal. If each is x, then the vertex angle is 2x, so x + x + 2x = 180°; therefore x = 45° and angle y = 90°. This makes B true and angle z = 45°, so E is true. The perpendicular bisector of XZ passes through Y and divides the triangle into two 45°-45°-90° triangles, which are isosceles, so A is true.

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