Question 37892
If you connect alternate vertices of an inscribed rectangle, it turns out to be a diameter of the circle.  This is because a 90 degree inscribed angle cuts off 180 degrees of arc.  This diameter's length can be found using the Pythagorean Theorem.
diam = sqrt(5^2 + 8^2) = sqrt(89)
radius = (1/2)sqrt(89)
A = pi(r^2)
A = (89/4)pi
C = 2(pi)r = pi(sqrt(89))
Area outside of rect = (89/4)pi - 40