The problem asks to find the size of angle $p$. We are given that a straight line is divided into three angles: $55^\circ$, $50^\circ$, and $p$.

1. Problem Description

The problem asks to find the size of angle $p$. We are given that a straight line is divided into three angles: $55^\circ$, $50^\circ$, and $p$.

2. Solution Steps

The sum of angles on a straight line is $180^\circ$. Therefore, we can write the equation:

$55^\circ + 50^\circ + p = 180^\circ$

Combining the known angles:

$105^\circ + p = 180^\circ$

Subtract $105^\circ$ from both sides of the equation:

$p = 180^\circ - 105^\circ$

$p = 75^\circ$

3. Final Answer

The size of angle $p$ is $75^\circ$.