Answer
The height of the rectangular television set is $\approx 27.1$ in.
Work Step by Step
Let $x =$ height of the rectangular television set
$a^{2} + b^{2} = c^{2}$
$x^{2} + 42^{2} = 50^{2}$
$x^{2} + 1764 = 2500$
$x^{2} = 736$
$x = \sqrt 736$
$x = 27.129...$
$x \approx 27.1$ in.