Find the length of the side x in simplest form with a rational denominator. i need help understanding these type of questions pls​

The variables should add up to equal 1

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .