In essence, adjacent angles are two angles side by side. Two adjacent angles can form a linear pair when they are created by two lines intersecting. So, in broad terms, they are adjacent on a flat plane (or a straight line), and together they make a 180° angle.
So since xd is 5 that means ad is 10 now you have 2 sides all you need is to find the last side you can use Pythagorean theorem and get 26 for db answer 26.