Because people make those substance out of other things
The answer to this question is theory
Einstein's famous equation, E = mc^2 relates the mass (m) of an object to energy (E). The speed of light (c), is the constant of proportionality. Einstein formulated the equation within his theory of special relativity. Indeed, a physical interpretation of this equation is that any given mass is equivalent to the energy given by the equation, if it were suddenly converted to energy. Therefore the answer to the question is true.
We know that there are 100 cm in 1 m, so we can use this to convert to meters:
Therefore we know that 
cm is equal to 2.41 m.
