Answer
(a) $\frac{2\sqrt[3] 2}{3}$
(b) $\frac{5\sqrt 3}{2}$
Work Step by Step
(a) $\sqrt[3] {\frac{16}{27}}=\frac{\sqrt[3] {16}}{\sqrt[3] {27}}=\frac{\sqrt[3] {8\times2}}{\sqrt[3] {3^3}}=\frac{\sqrt[3] {2^3\times2}}{3}=\frac{2\sqrt[3] 2}{3}$
(b) $\sqrt {\frac{75}{4}}=\frac{\sqrt {75}}{\sqrt 4}=\frac{\sqrt {25\times3}}{\sqrt {2^2}}=\frac{\sqrt {5^2\times3}}{2}=\frac{5\sqrt 3}{2}$