Question 142045
a line drawn from the center of the circles to the center of the chord is perpendicular to the chord


the radius of the larger circle (R), the radius of the smaller circle (r), and half of the chord (4)
__ from a right triangle with the larger radius as the hypotenuse


by Pythagoras, r^2+4^2=R^2 __ subtracting r^2 __ 16=R^2-r^2


multiplying by pi __ 16(pi)=(pi)R^2-(pi)r^2 __ this is the area between the circles