A line of length 15 cm at first lied on the vertical plane parallel to horizontal plane and then keeping one of its ends fixed turned 35 degrees with respect to horizontal plane and then turned 40 degrees with respect to vertical plane. What is the length of the line in front view?

First imagine the line in profile plane parallel to vertical plane as here we are asked to find the side view’s length so even if the line is rotated within the vertical plane the line length will not change and also rotated with respect to the vertical plane which is calculated as follows 15 x sin (35) = 8.6 cm.