Question

1. m∠hfx = ____

Explanation:

Step1: Recall triangle - angle - sum property

The sum of interior angles in a triangle $\triangle HFG$ is $180^{\circ}$. Let's first find the third - interior angle $\angle HFG$.
Let $\angle H = 39^{\circ}$ and $\angle G=26^{\circ}$. Then $\angle HFG=180^{\circ}-\angle H - \angle G$.
$\angle HFG = 180^{\circ}-39^{\circ}-26^{\circ}=115^{\circ}$.

Step2: Use linear - pair property

$\angle HFG$ and $\angle HFX$ form a linear pair. A linear pair of angles sums to $180^{\circ}$.
If $\angle HFG = 115^{\circ}$, then $\angle HFX=180^{\circ}-\angle HFG$.
$\angle HFX = 180^{\circ}-115^{\circ}=65^{\circ}$.

Answer:

$65^{\circ}$