Final answer:
The actual length of an object that appears to be 24mm under a x10 magnification is 2.4mm.
Step-by-step explanation:
The actual length of an object that looks 24mm under a x10 magnification can be calculated by dividing the observed size by the magnification factor. So, to find the actual length, you use the formula:
Actual length = Observed size / Magnification factor
In this case, the object appears to be 24mm in size under a 10x magnification, thus:
Actual length = 24mm / 10 = 2.4mm.
Hence, the actual size of the object is 2.4mm.