In the figure, what is the value of x?

Explanation

Choice D is correct. A quadrilateral's interior angles sum up to 360°. To find x, set up the equation 45 + 3x = 360. First, subtract 45 from both sides to get 3x = 315. Then, divide by 3 to solve for x, resulting in x = 105. This value ensures the angles add up correctly to 360°. Other options do not satisfy this requirement as their calculated sums are less than 360°.