What is the value of x in the triangle?

Answer:
B
Step-by-step explanation:
Since there are 2 congruent angles then the triangle is right isosceles.
The 2 legs of the triangle are therefore congruent ( both x )
Use Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
x² + x² = (3[tex]\sqrt{2}[/tex] )² , then
2x² = 18 ( divide both sides by 2 )
x² = 9 ( take the square root of both sides )
x = [tex]\sqrt{9}[/tex] = 3 → B