The length of segments ab is 24
C(1;2)
a = 1
b = 2
r = 4
(x-a)² + (y-b)² = r²
(x-1)² + (y-2)² = 4²
(x-1)² + (y-2)² = 16
The vertex at (1,2) and from there use this to make the graph.
over 1, up 1. over 2 up 4, over 3 up 9. and if you know its right side, you know its left side too.
