Question

The question fig. shows the 3D view of an object. Identify the correct number of visible surfaces.

• A. 11
• B. 14
• C. 12
• D. 13

Hint:

Count every separate closed region (face) visible in the 3D drawing, including the sloping roof faces, the steps, and the circular surface on the front face.

Answer 1

The Correct Option is D

Count the visible surfaces region by region in the drawing.
Roof (3 sloping faces): (1) the left triangular face, (2) the large right triangular face, (3) the thin sliver face along the back of the roof.
Box under the roof (3 surfaces): (4) the narrow right-hand vertical face, (5) the large front face carrying the circle, and (6) the circular surface itself.
Top surfaces (4): (7) the flat top at the back right, (8) the top of the left step, (9) the top of the middle step, (10) the top of the raised strip.
Vertical faces below (3): (11) the wall rising from the steps to the back-right top, (12) the notched front face at the left-front of the base, and (13) the large right-hand face of the base.
Total visible surfaces = 3 + 3 + 4 + 3 = 13 (the 12 plane faces plus the circular surface).
Answer: (4) 13