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 .