Given: Each interior angle is 135∘
Let each exterior angle be x.
Now, Each exterior angle +Each interior angle=180∘
∴135∘+x=180∘
x=180∘−135∘
=45∘
So, each exterior angle is 45∘
Also, Each exterior angle =360∘n
45∘=360∘n
n=360∘45∘
∴n=8
So, the number of sides is 8.