Q:

Pythagorean theorem: $A^2 + A^2 = C^2$ How to solve for $A$?

If I could only remember my algebra! So, I have a right triangle and I know the hypotenuse (28) and I know that the legs are the same length, so I have:

$A^2 + B^2 = C^2$
Where: $A=B$ and $C=28$

Pedestrian, I know, but how do I solve for $A$?
Many thanks!

A:

Put the numbers in the formula: $$2A^2=28^2=784$$
Now you have that $A^2=392$. You should know it from here. 

A:

Try this:
$A^2 + B^2 = C^2$
Since A = B and C = 28, then:
$A^2 + A^2 = 28^2$
$2A^2 = 28^2$
$A^2 = \frac{784}{2}$
$A = \sqrt{\frac{784}{2}}$

