Đáp án + Giải thích các bước giải:
$a)\quad \sqrt{10}.\sqrt{40}\\=\sqrt{400}=20\\ b)\quad \sqrt{5}.\sqrt{45}\\=\sqrt{225}=15\\ c)\quad \sqrt{52}.\sqrt{13}\\=\sqrt{676}=26\\ d)\quad \sqrt 2. \sqrt{162}\\=\sqrt{324}=18\\ e)\quad \sqrt{45.80}\\ = \sqrt{3600}=60\\ f)\quad \sqrt{90.6,4}\\=\sqrt{576}=24\\g)\quad \sqrt{75.48}\\=\sqrt{3600}=60\\ h)\sqrt{2,5.14,4}\\=\sqrt{36}=6$
