#### Answer

$74.8 cm$

#### Work Step by Step

We know that the angle of the smaller angle is 75 degrees. From this, we know that the height of the rectangle is:
$50(sin75)=h$
$h=48.3$
The shorter side is given by:
$s=50cos(75)=12.9$
This means that the length of the rectangle created is:
$l=70-12.9=57.1$
We use the Pythagorean theorem to find:
$ \sqrt{57.1^2+48.3^2}$
$74.8 cm$