Last quarter several puzzles involved geometric
figures
inscribed in other geometric figures. This issue's
puzzle is of
that type. The solution involves a fair amount of
trigonometry
and algebra. A triangle has sides of length 3, 5 and 7.
A
circle is inscribed inside the triangle (each side of the
triangle is tangent
to the circle). Find the exact (no
calculator decimals) radius of the circle.