WARM UP

PARALLEL & PERPENDICULAR

LINESObjectives:

To determine whether lines are parallel, perpendicular or neither.

To write equations of parallel lines and perpendicular lines.

Parallel Lines:Two lines in the same plane that do not intersect

Perpendicular Lines:Two lines in the same plane that intersect a

Perpendicular LinesThe equation of a perpendicular line has the opposite sign and reciprocal of the slope in the other.

Example:Line 1: Perpendicular Line:

Problem # 1: Writing an Equation of a Parallel LineA) A line passes through (12, 5) and is parallel to the graph of . What equation represents the line in slope-intercept form?

Problem # 1: Writing an Equation of a Parallel LineB) A line passes through (-3, -1) and is parallel to the graph of . What equation represents the line in slope-intercept form?

Problem #1Got It?

What is an equation in slope-intercept form of

the line that passes through (2, 15) and is

parallel to the graph of y =4x – 1?

Problem # 2: Classifying Lines

A) Are the graphs of 4y = -5x + 12 and parallel, perpendicular, or neither? Explain.

Problem # 2: Classifying Lines

B) Are the graphs of 4x – 3y = 9 and parallel, perpendicular, or neither? Explain.

Problem #2Got It?

Are the graphs of 6y = -x + 6 and parallel, perpendicular, or neither? Explain.

Problem # 3: Writing an Equation of a Perpendicular Line

A) A line passes through (2, 8) and is perpendicular to the graph of y = 2x + 1. What equation represents the line in slope-intercept form?

Problem # 3: Writing an Equation of a Perpendicular Line

B) Which equation represents the line that passes through (2, 4) and is perpendicular to the graph of ?

Problem #3Got It?

The graph of which equation passes through (10, 15) and is perpendicular to the graph of ?

Problem # 4: Solving a Real- World ProblemA) An architect uses software to design the ceiling of a room. The architect needs to enter an equation that represents a new beam. The new beam will be perpendicular to the existing beam, which is represented by the red line. The new beam will pass through the corner represented by the blue point. What is an equation that represents the new beam?

Problem # 4: Solving a Real- World Problem

B) Carla is using a coordinate grid to make a map of her hometown. She plots Main Street as shown. If 3rd Street is perpendicular to Main Street at (5, 7), what is an equation for 3rd Street?

Problem #4Got It?

What is an equation in slope-intercept form of the line that passes through (6, -7) and is

perpendicular to the line below?

HOMEWORK