Answer
$\angle FRE$ and $\angle FRH$
$\angle ERH$ and $\angle HRG$
$\angle HRG$ and $\angle GRF$
$\angle FRG$ and $\angle FRE$
Work Step by Step
We know that supplementary angles add up to $180^{o}$. In other words, they form a line. From the figure, we thus have the following supplementary angles:
$\angle FRE$ and $\angle FRH$
$\angle ERH$ and $\angle HRG$
$\angle HRG$ and $\angle GRF$
$\angle FRG$ and $\angle FRE$
