△ABC is an isosceles triangle. <B is the vertex angle. What is the measure of <C if the m<B = 90 degrees?(1 point)
Since triangle ABC is isosceles, it means that angle A and angle C are congruent. Also, since angle B is the vertex angle, it means that angle A and angle C are base angles.
In an isosceles triangle, the sum of the base angles is equal to 180 degrees.
Therefore, if angle B = 90 degrees, then the sum of angles A and C is 180 - 90 = 90 degrees.
Since angle A and angle C are congruent, it means that each angle measures 90/2 = 45 degrees.
Therefore, the measure of angle C is 45 degrees.