445°45°4[Graphs generated by this script: initPicture(-0.8,4.4,-0.8);path([[0,0],[4,0],[0,4],[0,0]]);path([[0,1],[1,1],[1,0]]);text([4/2,0],"4","below");text([0,4*0.8],"45°","belowright");text([4*0.85,0],"45°","aboveleft");text([0,4/2],"4","left")]

What is the best name for the figure above?



What is the length of the hypotenuse?  

42\displaystyle {4}\cdot\sqrt{{{2}}} =