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Answer:
20[tex]\pi[/tex]
Step-by-step explanation:
Circumference formula: [tex]2\pi r[/tex]
Since the diameter is 20, the radius will be half of the diameter
r=d/2, where d=20
r=20/2=10
C=[tex]2\pi r[/tex]
C=2(10)[tex]\pi[/tex]
C=20[tex]\pi[/tex]