Find the square of $15\dfrac{2}{3}$

$\Big[15\dfrac{2}{3}\Big]^2\\[1em] = \Big[\dfrac{47}{3}\Big]^2\\[1em] = \dfrac{47 \times 47}{3 \times 3}\\[1em] = \dfrac{2209}{9}\\[1em] = 245\dfrac{4}{9}$

$15\dfrac{2}{3} = 245\dfrac{4}{9}$