1. trapezoid ABCD is inscribed in a semicircle, as shown below. the length of base CD is 7, and the lengths of legs AD and BC are 3. Find the radius of the smicircle.
https://latex.artofproblemsolving.com/3/3/5/33547ff6030a8141f08e8ac03e41f09300c38b7f.png