The answer to the question above is the third choice, "a shelf on a wall". The shelf is usually made of rectangular pieces of materials that are then connected to each other to form quadrilaterals. The sides of the shelf are planes.
5•3=15, 3.5•3=10.5....... the regular length of the length and width is :::::: LENGTH= 10.5 feet..... HEIGTH=15 feet
