.
A quadrilateral contains an inscribed circle. The ratio of the perimeter of the quadrilateral to that of the circle is 4:3.
Find the ratio of the area of the quadrilateral to that of the circle.
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If a quadrilateral has/contains an inscribed circle, then the area of the quadrilateral is
=
,
where P is the quadrilateral's perimeter, and r is the radius of the inscribed circle.
It is well known fact. See the lesson Area of a quadrilateral circumscribed about a circle in this site.
From the other side, the circumference of the circle is
=
, and the area of the circle S is
=
.
Therefore,
=
:
=
.
Now recall that
=
, it is given.
Hence,
=
.
The solution is complete.