21: \(\sqrt{\dfrac{1}{4}}=\sqrt{\dfrac{1}{2^2}}=\dfrac{1}{2}\)
22: \(\sqrt{\dfrac{1}{9}}=\sqrt{\dfrac{1}{3^2}}=\dfrac{1}{3}\)
23: \(\sqrt{\dfrac{1}{16}}=\sqrt{\left(\dfrac{1}{4}\right)^2}=\dfrac{1}{4}\)
24: \(\sqrt{\dfrac{1}{25}}=\sqrt{\left(\dfrac{1}{5}\right)^2}=\dfrac{1}{5}\)
25: \(\sqrt{\dfrac{1}{36}}=\sqrt{\left(\dfrac{1}{6}\right)^2}=\dfrac{1}{6}\)
26: \(\sqrt{\dfrac{25}{9}}=\sqrt{\dfrac{5^2}{3^2}}=\sqrt{\left(\dfrac{5}{3}\right)^2}=\dfrac{5}{3}\)
27: \(\sqrt{\dfrac{49}{36}}=\sqrt{\dfrac{7^2}{6^2}}=\sqrt{\left(\dfrac{7}{6}\right)^2}=\dfrac{7}{6}\)
28: \(\sqrt{\dfrac{64}{81}}=\sqrt{\dfrac{8^2}{9^2}}=\sqrt{\left(\dfrac{8}{9}\right)^2}=\dfrac{8}{9}\)
29: \(\sqrt{\dfrac{100}{144}}=\sqrt{\dfrac{25}{36}}=\sqrt{\left(\dfrac{5}{6}\right)^2}=\dfrac{5}{6}\)
30: \(\sqrt{\dfrac{121}{225}}=\sqrt{\dfrac{11^2}{15^2}}=\sqrt{\left(\dfrac{11}{15}\right)^2}=\dfrac{11}{5}\)
\(21,\sqrt{\dfrac{1}{4}}=\dfrac{1}{2}\)
\(22,\sqrt{\dfrac{1}{9}}=\dfrac{1}{3}\)
\(23,\sqrt{\dfrac{1}{16}}=\dfrac{1}{4}\)
\(24,\sqrt{\dfrac{1}{25}}=\dfrac{1}{5}\)
\(26,\sqrt{\dfrac{1}{36}}=\dfrac{1}{6}\)
\(26,\sqrt{\dfrac{25}{9}}=\dfrac{5}{3}\)
\(27,\sqrt{\dfrac{49}{36}}=\dfrac{7}{6}\)
\(28,\sqrt{\dfrac{64}{81}}=\dfrac{8}{9}\)
\(29,\sqrt{\dfrac{100}{144}}=\dfrac{5}{6}\)
\(30,\sqrt{\dfrac{121}{225}}=\dfrac{11}{15}\)
