Question

A line AB of length 2 m is placed in 2nd quadrant and parallel to vertical plane and the end A and B are 0.5 m and 0.3 m away from the horizontal plane respectively. The length of the line in top view is ______ m.

(a) 1.98

(b) 1.97

(c) 1.936

(d) 2

This question was addressed to me in an internship interview.

The doubt is from Projection of Straight Lines Parallel to Plane topic in chapter Projection of Lines of Engineering Drawing

Answer 1

Right answer is (a) 1.98

For explanation: The distance between the projectors drawn from A and B to horizontal plane gives the length of line in top view given the line parallel to vertical plane. The difference in distances from A and B to horizontal plane is 0.2 (0.5-0.3). Given length is 2 m so required length is √(2^2-0.2^2 )= 1.98m.