Parallel and Perpendicular Lines Coordinate Geometry Parallel and Perpendicular Lines

PARALLEL x-axis l 2 units DOWN 4 units LEFT k 2 units DOWN m 2 units DOWN 4 units LEFT

Parallel Line All line that are parallel to each other have: Same value of gradient. No intersection point or the lines never meet except the lines are coincide to each other.

Exercise 1 State whether each of the following pair of gradients, m1 and m2 represents parallel lines or not. m1 = 2, m2 = ½ m1 = 1, m2 = -1 m1 = 1.5 , m2 = 3/2 m1 = 4, m2 = 1/8 Which pair of these equations are parallel? y = x – 2 , y = 2x + 8 2y = 2x – 4 , y = x – 3 4y = 3x – 1 , y = 4 + 3x

PARALLEL Word-Written Question (-6, 6) k 2 units DOWN 4 units LEFT x-axis Word-Written Question A line l that pass through point (-6,6) is parallel to a line k with equation y = (1/2)x + 4. Find the equation of line l.

PERPENDICULAR x-axis l m 2 units LEFT k 4 units UP 2 units DOWN

Perpendicular Line All line that are perpendicular to each other have: Negative reciprocal value of gradient. Example: …………… Conclusion: ……………. One intersection point.

Exercise 2 State whether each of the following pair of gradients, m1 and m2 represents perpendicular lines or not. m1 = 2, m2 = ½ m1 = 1, m2 = -1 m1 = 1.5, m2 = 3/2 Find the gradient of a line that is perpendicular to a line with gradient: 3/4 -2.5 -1 Which pair of these equations is perpendicular to each other? y = 6 – 2x , y = x – 1 y = (x/3) – 2 , y = 4 – 3x 3y = 2x – 2 , y = 5 – (3/2)x

Word-Written Question PERPENDICULAR l k 2 units DOWN (4, 1) 4 units LEFT x-axis Word-Written Question A line l that pass through point (4,1) is perpendicular to a line k with equation y = (1/2)x + 4. Find the equation of line l.

Congratulation!!! Don’t forget to play study at home.