Question

Áp dụng quy tắc khai phương một tích, hãy tính :

a) \(\sqrt{45.80}\)

b) \(\sqrt{75.48}\)

c) \(\sqrt{90.6,4}\)

d) \(\sqrt{2,5.14,4}\)

Answer 1

a)\(\sqrt{45.80}=\sqrt{9.400}=\sqrt{9}.\sqrt{400}=3.20=60\)

b) \(\sqrt{75.48}=\sqrt{25.3.16.3}=\sqrt{5^2.3^2.4^2}=5.4.3=60\)

c)\(\sqrt{90.6,4}=\sqrt{10.9.4.1,6}=\sqrt{4^2.3^2.2^2}=4.3.2=24\)

d) \(\sqrt{2,5.14,4}=\sqrt{\dfrac{25}{10}.\dfrac{144}{10}}=\sqrt{\dfrac{25.144}{100}}=\sqrt{\left(\dfrac{5.12}{10}\right)^2}=\dfrac{5.12}{10}=6\)

Answer 2

a) \(\sqrt{45.80}=\sqrt{9.400}=\sqrt{9}.\sqrt{400}=3.20=60\)

b)\(\sqrt{75.48}=\sqrt{25.3.3.16}=5.3.4=60\)

c)\(\sqrt{90.6,4}=\sqrt{9.64}=3.8=24\)

d)\(\sqrt{2,5.14,4}=\sqrt{\dfrac{25}{10}.\dfrac{144}{10}}=\sqrt{\dfrac{25.144}{100}=\dfrac{5.12}{10}=\dfrac{60}{10}=6}\)