Answer:
cos theta = adjacent/hypotenuse = [tex]\frac{2}{\sqrt{5} }[/tex]
Step-by-step explanation:
csc theta = hypotenuse/opposite = [tex]\sqrt{5}[/tex] /1 (reciprocal identity)
1^2 + b^2 = [tex]\sqrt{5}[/tex]^2 (pythagorean theorem)
b^2 = 5-1
b = 2
cos theta = adjacent/hypotenuse = 2/[tex]\sqrt{5}[/tex] (quotient identity)