+128731 Let D = (0, 0)
P = ( 2, 6 - sqrt (4^2 - 2^2) ) = (2 , 6 - sqrt (12) )
C = (4 ,0)
PC^2 = (4 - 2)^2 + (6- sqrt (12))^2
PC^2 = 4 + 36 - 12sqrt (12) + 12
PC^2 = 52 - 12sqrt (12)
PC^2 = 52 - 24sqrt (3) = 4 (13 - 6sqrt (3) )
PC = sqrt [ 4 ( 13 - 6sqrt (3) ) ] = 2 sqrt [ 13 - 6sqrt (3) ] ≈ 3.23
