1 answer
(click or scroll down)
Sketch the 2 buildings, mark the window on one of them.
Draw a horizontal from the window to the other building, mark it as 15m
(any horizontal line between the two buildings will be 15m )
From the window draw in lines to the top and bottom of the opposite building.
Mark your given angles. You have right-angled triangles.
Btw, I see no question asked in your problem.