Construct a triangle given one side and the opposing angle I am given one side of a triangle, and the _opposing_ angle. How can I construct the triangle, and / or the solution set?

Supposing you want to keep the given side fixed, you can draw the given angle at both its extremities, than draw the lines perpendicular to the added rays (the green ones in the picture) through the side extremities. These will meet in the center of the circle on which you can choose the third vertex of your triangle. ![enter image description here](