Answer:
90°
Step-by-step explanation:
Arc a subtends and angle of 45° to the circumference of the circle
We know that;
An angle subtended by an arc to the center of a circle is twice the angle subtended by the same chord to the center of the circle.
Therefore, if arc a subtends and angle of 45° to the circumference of the circle then;
a will be = 45 × 2
= 90°
