Which view shows the true size of a slanted surface?

• A. Auxiliary view
• B. Section view
• C. Isometric view
• D. Front view

Answer: (A)

When you want to see the actual size and shape of a surface that is tilted relative to the principal planes, you use an auxiliary view. This view is created by projecting onto a plane that is parallel to the slanted surface. Because the projection plane lies in the same orientation as the surface, measurements shown in the auxiliary view are not foreshortened—the surface appears in its true size and shape.

Other views won’t show true size for a slanted surface because they project onto planes that aren’t parallel to that surface. A front, top, or side view compresses or elongates the surface, so its dimensions aren’t true. An isometric view gives a 3D representation, which can still distort lengths unless the surface happens to align with the isometric axes. A section view reveals the cut surface, not the original slanted surface in true size.