The problem figure shows the top view of objects. Looking in the direction of the arrow, identify the correct elevation, from amongst the answer figures.
Show Hint
Look at the apex of each triangle: it points to the observer, so each object shows a central vertical edge in the elevation.
The top view shows four objects, each drawn as a triangle with its apex pointing down (towards the bottom of the sheet). The arrow points up, so the observer stands below the plan and looks upward. Step 1: Order the objects from left to right in the plan. They are: the top-left one, then the lower-left one, then the middle-right one, and finally the bottom-right one. Step 2: Depth. The objects nearest the observer are those lowest in the plan, namely the bottom-right and the lower-left objects. They partly hide the objects behind them: the lower-left object overlaps the top-left one, and the bottom-right object overlaps the middle-right one. The lower-left and middle-right objects only touch each other. Step 3: Each object is a triangular prism whose apex edge points towards the observer, so in the elevation every object appears as a rectangle with one vertical line (the apex edge) near its middle. All four rectangles must therefore carry a vertical line. Step 4: Check the answer figures. Answer figure 2 has no vertical line on the second rectangle, answer figure 3 has none on the third rectangle, and answer figure 4 has none on the fourth rectangle. Answer figure 1 shows four rectangles, each with its apex line, overlapping in exactly the order found in Step 2. Answer: (1) Answer figure 1
