We are given an angle of $45^{\circ}$ and we need to find the value of angle $y$, which is the supplement of $45^{\circ}$.

1. Problem Description

We are given an angle of $45^{\circ}$ and we need to find the value of angle $y$, which is the supplement of $45^{\circ}$.

2. Solution Steps

Supplementary angles add up to $180^{\circ}$. Thus, we have:

$y + 45^{\circ} = 180^{\circ}$

Subtract $45^{\circ}$ from both sides of the equation:

$y = 180^{\circ} - 45^{\circ}$

$y = 135^{\circ}$

3. Final Answer

The value of $y$ is $135^{\circ}$.