Answer:
D
x=5*sqrt(2)/2
Explanation:
since it is a right triangle, and one of the other angles is 45, we know that the last angle must also be 45 since the 3 interior angles must be 180
then using pythagroem theorem
sqrt(a^2+b^2)=c
sqrt(x^2+x^2) = 5
square both sides
x^2+x^2=25
2x^2=25
x^2=25/2
square root both sides
x= sqrt(25/2)=5/sqrt(2)
rationalize the demonominator by multiplying by sqrt(2)/sqrt(2)
x=5*sqrt(2)/2