Find the distance $d(A, B)$ between points $A$ and $B$.
\[
A(5,6) ; B(-4,18)
\]

Step 1 ：We are given two points A(5,6) and B(-4,18) and we are asked to find the distance between these two points.

Step 2 ：The distance between two points in a 2D plane can be calculated using the distance formula derived from the Pythagorean theorem. The distance between points \((x_1, y_1)\) and \((x_2, y_2)\) is given by: \[d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}\]

Step 3 ：In this case, \(x_1 = 5\), \(y_1 = 6\), \(x_2 = -4\), and \(y_2 = 18\). We can substitute these values into the formula to find the distance.

Step 4 ：By substituting the values into the formula, we get \[d = \sqrt{(-4 - 5)^2 + (18 - 6)^2} = \sqrt{81 + 144} = \sqrt{225}\]

Step 5 ：Finally, we find that the distance between points A and B is \(\boxed{15.0}\) units.