Vertical Angles

               Congruent means to have the same measure. You know you have vertical angles when the are separated by intersecting lines and are congruent to each other. A quadrilateral is a shape that has 4 sides. and it cannot have more than 4 sides or it wouldn't be a quadrilateral. If you only had one angle in a intersecting quadrilateral you can find the other angles by first finding the vertical angle of the one you already know, which will be the same so you add those 2  together and then you take the sum and subtract it from 360 then you take that number and divide it by 2 and that will give u each of the remaining angles.