Altitudes $\overline{XD}$ and $\overline{YE}$ of acute triangle $\triangle XYZ$ intersect at point $H$. If the altitudes intersect at a $123^\circ$ angle, and $\angle YXH = 26^\circ$, then what is $\angle HZX$ in degrees?

Stop cheating on our challenge problems!

To find $\angle HZX$, we can utilize the property that the sum of the angles in a triangle is $180^\circ$.

First, let's label the given information on the diagram:

[asy]
pair X,Y,Z,H,D,E;

X = (-5,0);
Y = (0,8);
Z = (4,0);
D = (0,0);
E = (0,6);
H = (0,2);

draw(X--Y--Z--cycle);
draw(X--D);
draw(Y--E);
draw(Z--H);

label("$X$",X,SW);
label("$Y$",Y,N);
label("$Z$",Z,SE);
label("$D$",D,S);
label("$E$",E,NW);
label("$H$",H,NE);
[/asy]

We know that $\angle YXH = 26^\circ$. Since $\angle XHY$ and $\angle XYZ$ are right angles (as they are altitudes), we can find $\angle XYZ$ by subtracting the known angles from $180^\circ$:

$\angle XYZ = 180^\circ - \angle YXH - \angle XHY = 180^\circ - 26^\circ - 90^\circ = 64^\circ$.

Now, let's find $\angle HZX$. Since $\angle HZX$ is the remaining angle in $\triangle XHZ$, we can find it by subtracting the known angles from $180^\circ$:

$\angle HZX = 180^\circ - \angle XHZ - \angle HZX$.

However, we don't know $\angle XHZ$ directly. To find it, we can utilize the fact that the sum of the angles in a triangle is $180^\circ$. In $\triangle XYZ$, we have:

$\angle XYZ + \angle XZY + \angle YZX = 180^\circ$.

We already found that $\angle XYZ = 64^\circ$. Also, since $\angle YXH$ and $\angle ZYX$ are right angles (as they are altitudes), $\angle XZY = 90^\circ - \angle YXH = 90^\circ - 26^\circ = 64^\circ$. Substituting these values into the equation above, we have:

$64^\circ + 64^\circ + \angle YZX = 180^\circ$.

Simplifying, we get:

$128^\circ + \angle YZX = 180^\circ$.

Subtracting $128^\circ$ from both sides, we find:

$\angle YZX = 52^\circ$.

Now we can substitute this value into our earlier equation to find $\angle HZX$:

$\angle HZX = 180^\circ - 64^\circ - 52^\circ = \boxed{64^\circ}$.