Let ABC be a triangle with\angle BAC = 90. A circle is tangent to the sides AB and AC at X and Y respectively, such that the points on the circle diametrically opposite X and Y both lie on the side BC. Given that AB = 6, find the area of the portion of the circle that lies outside the triangle.
Let the center of a circle be O and the midpoint of BC be M
Angle B = 45º
AM = sin( 45º) * 6
XY = 2/3 * AM (Segment XY is a side of a square inscribed in a circle.)
Area of an inscribed square As = XY2
r = sin(45º) * XY
Area of a circle Ac = r2pi
Area of a shaded segment A = (Ac - As) / 4 = pi - 2