Question

A line which is parallel to vertical plane is made to turn to an angle of 50 degrees with horizontal and then turned to an angle of 40 degrees with vertical plane and now the line has a length of 5 cm from top view. What is its true length?

(a) 7.77 cm

(b) 6.52 cm

(c) 3.8 cm

(d) 3.2 cm

The question was asked during an interview for a job.

This interesting question is from True Length of a Straight Line and its Inclinations with the Reference Planes in portion Projection of Lines of Engineering Drawing

Answer 1

Right answer is (a) 7.77 cm

Easy explanation: True length of line parallel to vertical plane and making angle with horizontal can be of two values either from top view or side view but from front view the length will be given length. As here it is given top view L=5/cosine (50).