Question

what is the value of $p$?

Explanation:

Step1: Identify supplementary angle pair

The angle $56.4^\circ$ and $p$ are supplementary, so their sum is $180^\circ$.

Step2: Solve for $p$

Subtract $56.4^\circ$ from $180^\circ$.
$p = 180^\circ - 56.4^\circ$

Answer:

$123.6^\circ$