Answer:
Step-by-step explanation:
Diameter in the coin is the distance from side to side.
The numbers in the ruler are showing the centimeters. Each line is a subdivision in ten parts between centimeter and centimeter (Each line is equal to 1mm).
As you can see in the ruler, in the edge of the coin, the ruler is showing 3.8cm
As 1cm = 10mm:
3.8cm * (10mm / 1cm) =
38mm is the diameter of the coin to the nearest milimeter