Question 34005
THE CORNER LINE BETWEEN 2 WALLS OF A ROOM FROM FLOOR TO ROOF IS PERPENDICULAR TO FLOOR LINE ALONG ANY OF THE WALLS.
WHEN YOU PUSH OPEN A DOOR IT MAKES AN ACUTE ANGLE WITH THE DOOR HINGE AT THE BEGINING AND INALLY MAKES 90 DEGREES OR A SLIGHTLY OBTUSE ANGLE WITH THE HINGE WHEN IT IS FULLY OPENED AND TOUCHES THE NEIGHBOURING WALL.
SAME THING HAPPENS WHEN YOU OPEN A BOOK TO READ..WE HAVE AN ACUTE ANGLE BETWEEN THE PAGES TO START WITH AND NORMALLY IN THE END IN THE REAING POSITION THE ANGLE IS OBTUSE BETWEEN THE PAGES.