Answer:
1.2 cm
Step-by-step explanation:
Quadrilateral circumscribing a circle is a quadrangle whose sides are tangent to a circle inside it (see attached diagram).
The area of circumscribed quadrilateral is
where is semi-perimeter and r is radius of inscribed circle.
In your case,
If a quadrilateral is circumscribed over the circle, then the sum of opposite sides is equal, so
so
Now
