I have attached an image of a sinusoidal damped oscillation that shows the two amplitudes of which ratio x = B 1 C 1 / B 2 C 2 {( x 1 / x 2 )in the question} is measured

here,

x is what is named decrement. In order to usually find the viscosity of the medium in which a pendulum oscillates and it's amplitude studied (or any other purpose), we define a term called logarithmic decrement,λ that is numerically equal to log(x).

Do give feedback on the answer (my first) and ask clarification anywhere if required.

I have attached an image of a sinusoidal damped oscillation that shows the two amplitudes of which ratio $x = B_1 C_1 / B_2 C_2$ (which is $x_1 / x_2$ in the question) is measured

Here, $$ x = e^\lambda = \frac{B_1C_1}{B_2C_2} = \frac{B_2C_2}{B_3C_3} $$

and $x$ is what is named decrement.

In order to usually find the viscosity of the medium in which a pendulum oscillates and it's amplitude studied (or any other purpose), we define a term called logarithmic decrement, $λ$ that is numerically equal to $\log(x)$.

I have attached an image of a sinusoidal damped oscillation that shows the two amplitudes of which ratio x = B 1 C 1 / B 2 C 2 {( x 1 / x 2 )in the question} is measured

here,

x is what is named decrement. In order to usually find the viscosity of the medium in which a pendulum oscillates and it's amplitude studied (or any other purpose), we define a term called logarithmic decrement,λ that is numerically equal to log(x).

Do give feedback on the answer (my first that has not been deleted ;) yet ) and ask clarification if required anywhere.

I have attached an image of a sinusoidal damped oscillation that shows the two amplitudes of which ratio x = B 1 C 1 / B 2 C 2 {( x 1 / x 2 )in the question} is measured

here,

x is what is named decrement. In order to usually find the viscosity of the medium in which a pendulum oscillates and it's amplitude studied (or any other purpose), we define a term called logarithmic decrement,λ that is numerically equal to log(x).

Do give feedback on the answer (my first) and ask clarification anywhere if required.