Final answer:
The ratio of the masses of two similar blocks can be found by comparing the volumes of the blocks, which are determined by the ratio of their side lengths cubed. By using the given side lengths, we can find that the ratio of their masses is 0.125.
Step-by-step explanation:
To find the ratio of their masses, we can use the relationship between the volumes and masses of similar objects. Since the blocks are similar, their volumes follow the ratio of their sides cubed. The ratio of their masses can be found by taking the cube root of the ratio of their volumes.
Let's call the mass ratio M1 and M2 for the two blocks, and the side lengths of the blocks L1 and L2. We have:
M1 / M2 = (L1 / L2)3
Substituting the given side lengths, L1 = 10cm and L2 = 20cm, we get:
M1 / M2 = (10 / 20)3 = 0.125
Therefore, the ratio of their masses is 0.125.