Straight Lines Straight line represent straights objects with negligible width and depth.
Slope of a line
The angle( say) θ made by the line l with positive direction of x-axis and measured anti clockwise is called inclination of the line. Obviously 0 ° ≤ θ ≤ 180 ° If θ is the inclination of a line l, then tan θ is called the slope or gradient of the line l.