Since sec θ=4>0 and sin θ>0 angle θ sit in first quadrant. By Pythagorean identities tan^2 θ+1 = sec^2 θ you can find tan θ which is
tan^2 θ+1 = 4^2
tan^2 θ+1 = 16
tan^2 θ=15
tan θ=√15 (only positive since θ is in first quadrant)
Now using reciprocal identities you can find cot θ =1/tan θ = 1/√15=√15/15