Câu 41: Trang 23 - sgk toán 9 tập 1
Biết $\sqrt{9,119}\approx 3,019$ . Hãy tính :
$\sqrt{911,9}$; $\sqrt{91190}$; $\sqrt{0,09119}$; $\sqrt{0,0009119}$
Bài Làm:
Ta có:
- $\sqrt{911,9}=\sqrt{9,119}.\sqrt{100}\approx 3,019,10\approx 30,19$
- $\sqrt{91190}=\sqrt{9,119}.\sqrt{10000}\approx 3,019.100\approx 301,9$
- $\sqrt{0,09119}=\sqrt{9,119}.\sqrt{0,01}\approx 3,019.0,1\approx 0,3019$
- $\sqrt{0,0009119}=\sqrt{9,119}.\sqrt{0,0001}\approx 3,019.0,01\approx 0,03019$