Answer
The third angle is $58^{\circ}$.
Work Step by Step
The measures of the three angles of a triangle equal $180^{\circ}$; therefore, if we have the measure of two angles, we can figure out the measure of the third angle.
$34 + 88 + x = 180$
Add the constants on the left side together:
$122 + x = 180$
Subtract $122$ from each side to solve for $x$:
$x = 58$
The third angle is $58^{\circ}$.
