If two non-vertical lines that are in the same plane has the same slope, then they are said to be parallel. Two parallel lines won"t ever intersect.

You are watching: Perpendicular lines intersect to form right angles If two non-vertical lines in the same plane intersect at a right angle then they are said to be perpendicular. Horizontal and vertical lines are perpendicular to each other i.e. the axes of the coordinate plane.

Example

Compare the slope of the perpendicular lines The slope of the red line:

\$\$m_1=frac-3-22-left ( -3 ight )=frac-55=-1\$\$

The slope of the blue line

\$\$m_2=frac2-left ( -2 ight )3-left ( -1 ight )=frac44=1\$\$

The slopes of two perpendicular lines are negative reciprocals.

See more: How Many Pints Are In 32 Ounces To Pints, Convert 32 Ounces To Pints

The product of the slopes of two perpendicular lines is -1 since

\$\$mcdot -frac1m=-1,: : where: : m_1=m: : and: : m_2=-frac1m\$\$

## Video lesson

Are these two line parallel? More classes on this subject
Algebra 1Formulating linear equations: Writing linear equations using the slope-intercept formAlgebra 1Formulating linear equations: Writing linear equations using the point-slope form and the standard form

## Next Chapter:

FORMULATING LINEAR EQUATIONS – Scatter plots and linear models
Search
Math Playground
All courses
Pre-Algebra
All courses
Algebra 1
All courses
Discovering expressions, equations and functions
Discovering expressions, equations and functions
Exploring real numbers
Exploring real numbers
How to solve linear equations
How to solve linear equations
Visualizing linear functions
Visualizing linear functions
Formulating linear equations
Formulating linear equations
Linear inequalities
Linear inequalities
Systems of linear equations and inequalities
Systems of linear equations and inequalities
Exponents and exponential functions
Exponents and exponential functions
Factoring and polynomials
Factoring and polynomials 