Answer:
0.065354330709 inch
Step-by-step explanation:
1 millimeter is equal to 0.03937007874 inches, so 1.66 mm is 0.065354330709 inches.
This comes from the definition 1 inch = 2.54 cm
so 1 inch = 25.4 mm. Divide by 25.4 and get:
0.03937007874 inch = 1 mm
