Answer:
D. 5
Explanation:
Applying,
cos∅ = adjacent/Hypotenuse
From the diagram,
Given: ∅ = 45°, adjacent = s, hyptenuse = 5√2
Therefore,
cos45° = s/5√2
make s the subject of the equation
s = cos45°×5√2
s = (1/√2)(5√2)
s = 5
Hence the right answer is D. 5