If $A$ be the area of a right angled triangle and $b$ be one of the sides containing the right angle, then the length of altitude on the hypotenuse is :
- $\frac{2Ab}{\sqrt{4b^{4}+A^{2}}}$
- $\frac{Ab}{\sqrt{b^{4}+4A^{2}}}$
- $\frac{2Ab}{\sqrt{b^{4}+4A^{2}}}$
- $\frac{Ab}{\sqrt{4b^{4}+A^{2}}}$