Ответ:

  1. \(\sqrt{2.5^2-1.5^2}=\sqrt{6.25-2.25}=\sqrt4=2\).
  2. \(\sqrt{0.5^2-0.4^2}=\sqrt{0.25-0.16}=\sqrt{0.09}=0.3\).
  3. \(\sqrt{4\cdot(0.3^2+0.07)}=\sqrt{4\cdot(0.09+0.07)}=\sqrt{0.64}=0.8\).

Ответ: 1) 2; 2) 0,3; 3) 0,8.