Question 702666
Isosceles!  If right triangle has a 45 degree angle, then the other angle not 90 degrees is also 45 degrees.  Two sides are equal, too.  This triangle is half a square.


Let s be length of the legs and let h be the hypotenuse.


Area, A=(1/2)s^2, meaning {{{s=sqrt(2*A)}}}


The two length s meet at the right-angle.
{{{h^2=s^2+s^2}}}, ... and you do the steps,... {{{h=s*sqrt(2)}}}


Perimeter is the sum of the lengths that make the triangle.
Perimeter is {{{s+s+h}}}
{{{perimeter=2*sqrt(2*A)+s*sqrt(2)}}}