Answer:
18.38
Explanation:
since this triangle is a right-angled triangle and one its angles equals 45° then it's an isosceles right triangle which means that the side opposite 45° (the side to the left) is equal to 13 too.
so according to pythagoras theorem c = √(a²+b²)
x =√(13²+13²)
x = √(169+169)
x = √338
x ≈ 18.38
note: in the question it's mentioned to find y! and I believe it is just an error! it's about to find x and that's more resonable!
