Final answer:
The exact circumference of either face of the coin with a diameter of 18mm in terms of meters is π × 0.018m, which can be rounded to 0.05655m to five significant figures.
Step-by-step explanation:
The circumference of a circle can be calculated using the formula πd, where π (pi) is approximately 3.14159 and d is the diameter of the circle. Given that the diameter of the coin is 18mm, we can substitute this value into our formula to find the circumference. The circumference C in millimeters would be C = π × 18mm. To convert this into meters, we simply divide by 1000, because there are 1000 millimeters in a meter.
C = π × 0.018m
Using the value of π (around 3.14159), the exact circumference of the coin in meters will be:
C = 3.14159 × 0.018m = 0.05654742m
However, since we are looking for an exact value, we will leave our answer in terms of π, which yields:
C = π × (18/1000)m
Therefore, the exact circumference of either face of the coin in terms of meters is π × 0.018m, or simplified, 0.05655m when rounded to five significant figures.