Question

A line of length 15 cm at first lied on the profile plane parallel to horizontal plane and then keeping one of its ends fixed turned 30 degrees with respect to horizontal plane and then turned 50 degrees with respect to profile plane. What is the length of the line in side view?

(a) 9.6 cm

(b) 12.99 cm

(c) 7.5 cm

(d) 11.49 cm

This question was posed to me in an interview.

This key question is from Projection of Line Inclined to both the Planes topic in section Projection of Lines of Engineering Drawing

Answer 1

Right option is (a) 9.6 cm

The best I can explain: First imagine the line in profile plane parallel to horizontal plane as here we are asked to find the side view’s length so even if the line is rotated within the profile plane the line length will not change and then rotated with respect to the profile plane which is calculated as follows 15 x cos (50) = 9.6 cm.