Answer:
<u>Arc AD = 43°</u>
Step-by-step explanation:
<em>Image is attached.</em>
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When an angle subtends from an Arc to the center, the measure of the Arc and the Angle are same. Now, looking at the figure,
Arc AB = 180 (since this is an Arc subtending the diameter)
Arc DC = 90 degrees since the central angle is 90
So,
Arc AD + Arc CB = 180 - 90 = 90
Arc AD and Arc CB have the same measures as the central angle it created (terms in x). So we can write:
Arc AD + Arc CB = 90
7x + 1 + 9x - 7 = 90
We can solve for x:

The central angle AD is:
AD = 7x + 1 = 7(6) + 1 = 43
Also, Arc AD is same, thus:
<u>Arc AD = 43°</u>