Answer:
B
Step-by-step explanation:
Using the cosine ratio in the right triangle and the exact value
cos45° = [tex]\frac{1}{\sqrt{2} }[/tex] , then
cos45° = [tex]\frac{adjacent}{hypotenuse}[/tex] = [tex]\frac{3}{c}[/tex] = [tex]\frac{1}{\sqrt{2} }[/tex] ( cross- multiply )
c = 3[tex]\sqrt{2}[/tex]
