Answer:
cos Θ =

Explanation:
Given the angle passes through (4, 5 ) then the right triangle with sides 4 and 5 has hypotenuse h given by
h² = 4² + 5² = 16 + 25 = 41 ( take the square root of both sides )
h =

In relation to Θ, 4 is adjacent and 5 is opposite, thus
cos Θ =
=
