

For example, if the slope of a line with the equation y = 4x + 3 is 4. It should be noted that the slope of any two parallel lines is always the same. The value of 'm' determines the slope or gradient and tells us how steep the line is. The equation of a straight line is generally written in the slope-intercept form represented by the equation, y = mx + b, where 'm' is the slope and 'b' is the y-intercept.

Parallel Lines can be easily identified with the basic properties given below. Vertically Opposite Angles: Vertically opposite angles are formed when two straight lines intersect each other and they are equal in measure.Consecutive Interior Angles: Consecutive interior angles or co-interior angles are formed on the inside of the transversal and they are supplementary.Alternate Exterior Angles: Alternate exterior angles are formed on either side of the transversal and they are equal in measure.Alternate Interior Angles: Alternate interior angles are formed on the inside of two parallel lines that are intersected by a transversal.In the given figure, there are four pairs of corresponding angles, that is, ∠a = ∠e, ∠b = ∠f, ∠c = ∠g, and ∠d = ∠h Corresponding Angles: It should be noted that the pair of corresponding angles are equal in measure.

Given below are the pairs of angles formed by the two parallel lines L1 and L2. Each angle has been labeled using an alphabet. Eight separate angles have been formed by the two parallel lines and a transversal. The parallel lines are labeled as L1 and L2 that are cut by a transversal. Observe the following figure to see parallel lines cut by a transversal. While some angles are congruent (equal), the others are supplementary. When any two parallel lines are intersected by another line called a transversal, many pairs of angles are formed.
