Brainliest anwser to the person who

To find hypotenuse multiply by sqrt of 2, which is equal; To find the legs length divide by sqrt 2. 

45 degrees  - 45 degrees - 90 degrees
13 sqrt2/ sqrt 2 = about 9.2 units

The diagonal of a square divides into two 45 degrees - 45 degrees - 90 degrees triangle. 

y = 45; In a 45 degrees - 45 degrees - 90 degrees triangle, the legs (L) are congruent (L = L), and length of hypotenuse h is sqrt 2 times the length of a leg (h = l sqrt2). So, if hypotenuse is 13, then x sqrt 2 = 13.

Solving for X:
x sqrt 2/ sqrt 2 = 13/ sqrt 2

x = 13/ sqrt 2 * sqrt 2/sqrt 2

= 13 sqrt 2/2

Hence: x = 13 sqrt 2/2 about 9.2 units;  y = 45

Your answer would be, Letter Choice (B) 13 sqrt2/2

Hope that helps