Answer
$\lambda_1 \gt \lambda_2 \gt \lambda_3$
Work Step by Step
Let $v$ be the speed of sound. Given the frequency $f$, we can write an expression for the wavelength.
$\lambda = \frac{v}{f}$
From this equation, we can see that the wavelength decreases as the frequency increases. We know that $f_3 \gt f_2 \gt f_1$. Therefore:
$\lambda_1 \gt \lambda_2 \gt \lambda_3$.
