Since the picture was enlarged by a factor of 100, divide 29 centimeters (the length in the photo) by 100 (the factor of enlargement) to get the actual length.
29/100 = 0.29 centimeters
Thus, the actual length of the deer tick is 0.29 centimeters.
If you need the length in millimeters, multiply 0.29 with 10, and you get 2.9 millimeters.
Have an awesome day! :)
