If a vector 2î + 3ĵ + 8k̂ is perpendicular

If a vector 2î + 3ĵ + 8k̂ is perpendicular to the vector 4ĵ - 4î - αk̂ , then the value of α is

For two vectors to be perpendicular to each other
A^{^→} . B^{^→} = 0
(2î + 3ĵ + 8k̂) . (4ĵ - 4î - αk̂) = 0
–8 + 12 + 8α = 0

α = -	4	= -	1
	8		2