Question

Which one of the answer figures, shows the correct view of the 3 - D problem figure, after the problem figure is opened up ?

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

The object is a prism with an eight-sided end profile (base, tall side, three treads, two risers and a slope), so the net needs eight rectangles in the strip.

Answer 1

The Correct Option is C

The solid is a prism with a staircase-shaped end face. Going round the end face you meet the long base, the tall left side, the top tread, a riser, a second tread, a second riser, a third tread and the sloping face: eight sides in all.
When the solid is opened up, each side face becomes a rectangle and they form a strip of eight rectangles in this order, with the two end faces (staircase shapes) attached on both sides of the rectangle that belongs to the base, the longest side.
Thus the net must show eight rectangles. Option (1) shows nine (the upper part has an extra dividing line), Option (2) shows seven (a dividing line is missing in the lower part) and Option (4) also shows seven (a dividing line is missing in the lower part). Option (3) has the right eight rectangles: two above the base rectangle (the tall side and the top tread) and five below it (the risers, treads and the slope). So Option (3) is correct.
Answer: (3) Option (3) figure