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1. Select the first tangent object, close to the point of tangency.
2. Select the second tangent object, close to the point of tangency.
3. Size the circle with the mouse; the arc will be cut from this circle. Or enter the radius, diameter, or circumference in the Inspector Bar.
4. Move the cursor to either side of the arc to determine the arc segment that will remain.

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Tan gent Arc of Fixed Size

By default, Tangent to 2 Entities creates the smallest circle that touches two objects, and the arc is cut from this circle. To fix the size of the circle, enter the radius, diameter, or circumference in the Inspector Bar and lock it, but do not press Enter. When you move the cursor, the circle size remains constant.
Select the second tangent object.
The fixed-sized tangent circle, then arc, is created.