Calculate the Fourth Angle in a Trapezoid: Given Angles 110°, 130°, and 70°

The sum of angles in a trapezoid is 360 degrees.

Therefore:

$360=A+B+C+D$

Let's substitute the known data into the above formula:

$360=110+130+70+D$

$360=310+D$

We'll move terms and maintain the appropriate sign:

$360-310=D$

$50=D$