Answer:
B. 9/20[tex]\pi[/tex]
Step-by-step explanation:
the circumference is 2[tex]\pi[/tex]r. Since the radius is one, that would be 2[tex]\pi[/tex].
81/360=0.225, or 22.5% of the circumference. 22.5% of 2[tex]\pi[/tex] is 0.45[tex]\pi[/tex]. 0.45=9/20, so the answer is B.
CHECK: 2[tex]\pi[/tex] = 6.283
6.283x0.225=0.14137, or 9/20[tex]\pi[/tex]
