Can someone please help me.

Answer:10√2
Step-by-step explanation:
∆ABC is a right angle triangle
Angle A + Angle B + angle C = 180
There angel B = 180-135= 45
Angle A = Angle B
Therefore AC= BC=10
By Pythagoras ppt AB^2=10^2 +10^2
=100+100
=√200
=10√2