Question

A line of length 20 cm at first lied on the profile plane parallel to vertical plane and then keeping one of its ends fixed turned 40 degrees with respect to vertical plane and then turned 20 degrees with respect to profile plane. What is the length of the line in top view?

(a) 18.79 cm

(b) 6.8 cm

(c) 12.85 cm

(d) 15.32 cm

The question was asked in an internship interview.

I'm obligated to ask this question of Projection of Line Inclined to both the Planes topic in portion Projection of Lines of Engineering Drawing

Answer 1

The correct option is (c) 12.85 cm

Explanation: First imagine the line in profile plane parallel to vertical plane as here we are asked to find the top view’s length so even if the line is rotated within the horizontal plane the line length will not change and then rotated with respect to the horizontal plane which is calculated as follows 20 x sin (40) = 12.85 cm.