Friday Dec 14 6.5 Perpendicular Lines
Warm-Up Are the lines Parallel? SHOW YOUR WORK! 4x + 2y = 8 and 8x + 4y = 12 2. Write the equation of the line in slope intercept form that contains the point (3,-1) and has a slope of ¾ . 3. Graph the line x=1
Homework 4.9 Check Y = x+1 2. y = -2x
Find the reciprocal of the following: 2. 9
Find the opposite: 1. 3 2. -12 3. ¾ 4. -½
Find the opposite AND reciprocal: 1. -5 2. 0 3. 4.
Perpendicular lines have slopes that are opposite, reciprocals of each other. **Opposite means Change from negative to positive Or from Positive to negative Reciprocal means **flip your fraction**
Intersect to form RIGHT angles. (90 degree angles) Perpendicular Lines Intersect to form RIGHT angles. (90 degree angles)
What do you notice about the equations of the perpendicular lines? Red Line: Blue Line:
Are the lines perpendicular? 1.
2.
Any horizontal line is perpendicular to a vertical line And vice versa.
Write the equation of the line that is perpendicular to the line and goes through the point (0, 2). Step 1: Identify the slope Step 2: Find the perpendicular slope of the original slope. Step 3: Use the slope and the point to write an equation in point slope form. Step 4: Convert the equation from point slope form to slope-intercept form.
2. Write the equation of the line that contains (1,8) and is perpendicular to
A bike path for a new city park will connect the park entrance to Park Road. The path will be perpendicular to Park Road. Write an equation for the line representing the bike path.
Exit Ticket: Compare the slopes of parallel lines. Compare the slopes of perpendicular lines.
Homework HW 4.10