If (a + b):(b + c):(c + a) = 7:6:5 and a + b + c = 27, then what will be the value of 1/a: 1/b :1/c?

$$3\sqrt{ {72.9\over0.4096}}$$ is equal to : 

What is the value of X ?, if 7580 - X = 3440

The value of   $$ {(0.03)^2 - (0.01)^2}\over 0.03-0.01 $$

The value of $${\sqrt{40+\sqrt{9\sqrt{81}}} }$$ is

If $$ {\sqrt{1+{473\over{256}}}=1+{x\over 16}}$$ then what does x equal to ?

Simplify the following equation
$$ {\sqrt{(1-sin^{2}θ) ÷{(1-cos^{2}θ)}}}$$

The value of $$ \sqrt{11.981+7\sqrt{1.2996}}$$ is closest to