[Isosceles, Inscribed, and Circumscribed Trapezoids] Area of a Trapezoid

An isosceles trapezoid with a lateral side equal to 9 has an inscribed circle with a radius of 4. Find the area of the trapezoid.
Since the trapezoid is circumscribed about a circle, its height is equal to the diameter of this circle, and the sum of the bases is equal to the sum of the lateral sides, i.e., 18. Then the midline of the trapezoid (half the sum of the bases) is 9, and the area is $9 \cdot 8=72$

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