Answer:
The measure of arc CD is

Explanation:
see the attached figure with letters to better understand the problem
we know that
The measure of arc CD is equal to the angle CAD by central angle
The measure of angle CAD is equal to the angle CAB multiplied by 2
Find the measure of angle CAB
In the right triangle ABC


substitute the values


Find the measure of angle CAD


therefore
The measure of arc CD is
