Points A (-1, 2) and B (3, 12)are the endpoints of a diameter of a circle graphed in a coordinate plane. How many square units are in the area of the circle? Express your answer in terms of .
The center of the circle is the midpoint = ( [ 3 -1 ] / 2 , [ 12 + 2 ] / 2 ) = (1, 7)
The square of the radius = ( 3 - 1)^2 + ( 12 - 7)^2 = 2^2 + 5^2 = 29
The area of the circle = 29 pi units^2