projection of a line at horizontal plane is a point.line is
Answers
Answer:
There can be three conditions of a line in a space with respect to a horizontal plane.
1. Line is along the horizontal plane:
If the line is along the horizontal plane , it means the line is making angle 0 with the horizontal plane so the whole length will be the projection of the line on the horizontal plane.
Projection of line on the horizontal plane= length . cos 0
= length .1
= length
projection of line on the vertical plane = length × cos 90
=0
= point
2.Line is making an angle β with the horizontal
If the line makes an angle β with the horizontal then
the projection of line on the horizontal plane= length× cosβ
the projection of line on the vertical plane = length × cos (90-β0
= length×sin 90
3.Line is making an angle of 90 with the horizontal plane
the projection of line on the horizontal plane= length× cosβ
=length × cos 90
= 0, point
projection of line on the vertical plane = length × cos (90-90)
= length × 1
= whole length of line