we know that the triangle is an isosceles, thus it was twin sides stemming from a common vertex, and the vertex is located half-way of the base made by the twin sides.
Check the picture below.
Answer: 4
Step-by-step explanation: 4 is correct. Since vertex C is not collinear with A and B, it needs to lie on the line x = 4 to ensure that sides AC and BC are congruent.
