It depends on the type of ruler you are using. Depends if you are using a just metric unit ruler or if you are using a yard/meter stick. The measurements should be written along the edge of the ruler.
1-7/8 inches
See if you can find a part of the ruler where there are 9 little marks between the inch divisions: that section of the ruler may be marked as "10ths" or "TENTHS". Each of the gaps between these marks is 0.1 inch so you want 8 gaps.
3.166667 inches is 3.166667 inches, whether on a ruler or anywhere else.
It's between 9/16 and 5/8
0.32999999999999996
1-7/8 inches
41 and 3/8
Almost 3
On a 12 inch ruler, the 1/3 point would be 12/3, or at 4 inches.
Between 7/8 and 15/16
3.875 is the same as 3 and 7/8 inches on a ruler
Where is 0.71 inches on the ruler
See if you can find a part of the ruler where there are 9 little marks between the inch divisions: that section of the ruler may be marked as "10ths" or "TENTHS". Each of the gaps between these marks is 0.1 inch so you want 8 gaps.
3.166667 inches is 3.166667 inches, whether on a ruler or anywhere else.
It's between 9/16 and 5/8
a little over 6 1/8 inches, unless it's a 10ths ruler it may mot have a mark to indicate tenths
94 mm on a ruler is between 90 mm and 95 mm. On a typical ruler containing both mm and inches scales, where the scales are reversed with respect to each other, 94 mm is opposite 8 5/16 inches.