Final answer:
In an isosceles triangle ABC, if angle A = angle B, then the possible measures for angle A or angle B are options b) 45° and c) 55°.
Explanation:
In an isosceles triangle, angles opposite the congruent sides are also congruent. Given that angles A and B in triangle ABC are equal, let's consider their possible measures.
If angle A is 45°, then angle B will also be 45° since they are equal in an isosceles triangle. This satisfies the condition of angle A being equal to angle B in the triangle.
Similarly, if angle A is 55°, angle B will also be 55°, maintaining the equality of angles in the isosceles triangle. These two options, 45° and 55°, align with the property of an isosceles triangle where the base angles (angles A and B) are equal.
However, options 35° and 65° are not possible as they do not meet the condition of having equal measures for angles A and B in an isosceles triangle.
Therefore, considering the property of an isosceles triangle where angles opposite equal sides are congruent, the valid measures for angle A or angle B in this case are 45° and 55°, as provided in options b) and c).