The measures of the three of the interior angles of a quadrilateral are 60°, 110°, and 90°. What is the measure of the fourth angle of this quadrilateral?
The answer is C. 100 because the total measure of a quadrilateral is 360. When you add up the 3 interior angle measures, it adds up to 260. Then you subtract 360-260 to get 100 as the fourth angle measure. Hope that this helped!