Arrange the given fractions in descending order:

(i) $\dfrac{5}{17}, \dfrac{4}{9}, \dfrac{7}{12}$

(ii) $\dfrac{7}{12}, \dfrac{11}{36}, \dfrac{37}{72}$

(i) $\dfrac{5}{17}, \dfrac{4}{9}, \dfrac{7}{12}$

LCM of 17, 9 and 12 = 612.

Write the given fractions as equivalent like fractions.

$\Rightarrow \dfrac{5}{17} = \dfrac{5 \times 36}{17 \times 36} = \dfrac{180}{612} \\[1em] \Rightarrow \dfrac{4}{9} = \dfrac{4 \times 68}{9 \times 68} = \dfrac{272}{612} \\[1em] \Rightarrow \dfrac{7}{12} = \dfrac{7 \times 51}{12 \times 51} = \dfrac{357}{612}$

As 357 > 272 > 180,

$\dfrac{357}{612} \gt \dfrac{272}{612} \gt \dfrac{180}{612} \Rightarrow \dfrac{7}{12} \gt \dfrac{4}{9} \gt \dfrac{5}{17}$.

Hence, the given fractions in descending order are $\dfrac{7}{12}, \dfrac{4}{9}, \dfrac{5}{17}$.

(ii) $\dfrac{7}{12}, \dfrac{11}{36}, \dfrac{37}{72}$

LCM of 12, 36 and 72 = 72.

Write the given fractions as equivalent like fractions.

$\Rightarrow \dfrac{7}{12} = \dfrac{7 \times 6}{12 \times 6} = \dfrac{42}{72} \\[1em] \Rightarrow \dfrac{11}{36} = \dfrac{11 \times 2}{36 \times 2} = \dfrac{22}{72} \\[1em] \Rightarrow \dfrac{37}{72} = \dfrac{37}{72}$

As 42 > 37 > 22,

$\dfrac{42}{72} \gt \dfrac{37}{72} \gt \dfrac{22}{72} \Rightarrow \dfrac{7}{12} \gt \dfrac{37}{72} \gt \dfrac{11}{36}$.

Hence, the given fractions in descending order are $\dfrac{7}{12}, \dfrac{37}{72}, \dfrac{11}{36}$.