The angles in a quadrilateral always add up to 360 degrees.
To understand why, consider a quadrilateral, which is a four-sided shape. You can think of the quadrilateral as being composed of two triangles. Since the angles in a triangle add up to 180 degrees, and a quadrilateral can be divided into two triangles, we can add the angles like this:
180 degrees (first triangle) + 180 degrees (second triangle) = 360 degrees.
This property holds true for all types of quadrilaterals, whether they are squares, rectangles, trapezoids, or irregular quadrilaterals. By knowing this, it becomes easier to solve problems related to geometry that involve quadrilaterals, such as finding missing angles.