If the three angles of a quadrilateral are 25°, 170°, and 75°, what is the measure of the fourth angle?
一个四边形三个角的度数分别是25°、170°、75°，则第四个角的度数是多少度．
<gadget id="calculator">360 - 25 - 170 - 75</gadget>
<output>90</output>

<result>90</result>