L = illuminance
A = surface
i = intensity
L = i / A ==: i = L * A
i = 6 lux * 4 m^2 = 24 lumen
Hmm, I will come back to this one just to help. :)
the International System of Units, the fundamental units are: The meter (symbol: m), used to measure length. The kilogram (symbol: kg), used to measure mass. The second (symbol: s), used to measure time. The ampere (symbol: A), used to measure electric current.
Answer:
I think it's how far out the water goes from the beach before the tsunami because before tsunami usually the water goes back way behind the tide before tsunami and that tells them everything they need I think