Two circles are concentric if they have the same center. which equation represents a circle that is concentric with the circle shown but has a radius that is twice as large? (x – 4)2 + (y – 6)2 = 4 (x – 4)2 + (y – 6)2 = 16 (x – 6)2 + (y – 4)2 = 16 (x – 6)2 + (y – 4)2 = 4