The greatest length of a measuring tape that can be used to measure exactly 52m and 36m is ______?

None of these

To find the greatest length of a tape that can measure both 52 m and 36 m exactly, we need the HCF (Highest Common Factor) of 52 and 36.

Step-by-step:

Factors of 52: 1, 2, 4, 13, 26, 52

Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36

Common factors: 1, 2, 4

Greatest common factor = 4