Relative to an origin O, the position vectors of the points A, B and C are given by

\(\overrightarrow{OA} = i - 2j + 4k, \quad \overrightarrow{OB} = 3i + 2j + 8k, \quad \overrightarrow{OC} = -i - 2j + 10k.\)

1. Use a scalar product to find angle \(ABC\).
2. Find the perimeter of triangle \(ABC\), giving your answer correct to 2 decimal places.