Answer:
The circumference of clock is, 53.38 cm
Explanation:
Circumference(C) of the circle is given by:
....[1]
where, r is the radius of the circle.
As per the statement:
the radius of a clock face is 8.5 centimeters
⇒r = 8.5 cm
Use

Substitute the given values in [1] we have;

Simplify:
C = 53.38 cm
Therefore, the circumference of clock is, 53.38 cm