All Intermediate Geometry Resources
Example Questions
Example Question #1 : How To Find The Equation Of A Perpendicular Line
Suppose a perpendicular line passes through and point . Find the equation of the perpendicular line.
Find the slope from the given equation . The slope is: .
The slope of the perpendicular line is the negative reciprocal of the original slope.
Plug in the perpendicular slope and the given point to the slope-intercept equation.
Plug in the perpendicular slope and the y-intercept into the slope-intercept equation to get the equation of the perpendicular line.
Example Question #4 : How To Find The Equation Of A Perpendicular Line
Find a line perpendicular , but passing through the point .
Since we need a line perpendicular to we know our slope must be . This is because perpendicular lines have slopes that are negative reciprocals of each other. In order for our new line to pass through the point we must use the point slope formula. Be sure to use the perpendicular slope.
Example Question #7 : How To Find The Equation Of A Perpendicular Line
A line is perpendicular to the line of the equation
and passes through the point .
Give the equation of the line.
A line perpendicular to another line will have as its slope the opposite of the reciprocal of the slope of the latter. Therefore, it is necessary to find the slope of the line of the equation
Rewrite the equation in slope-intercept form . , the coefficient of , will be the slope of the line.
Add to both sides:
Multiply both sides by , distributing on the right:
The slope of this line is . The slope of the first line will be the opposite of the reciprocal of this, or . The slope-intercept form of the equation of this line will be
.
To find , set and and solve:
Add to both sides:
The equation, in slope-intercept form, is .
To rewrite in standard form with integer coefficients:
Multiply both sides by 5:
Add to both sides:
or
Example Question #1 : How To Find The Slope Of A Perpendicular Line
Any line that is perpendicular to must have a slope of what?
Two lines are perpendicular if and only if their slopes are negative reciprocals of each other. To find the slope, we must put the equation into slope-intercept form, , where equals the slope of the line. First, we must subtract from both sides of the equation, giving us . Next, we must divide both sides by , giving us . We can now see that the slope of this line is . Therefore, any line that is perpendicular to this one must have a slope of .
Example Question #1 : How To Find The Slope Of A Perpendicular Line
What is the slope of any line perpendicular to ?
The slope of a perpendicular line is the negative reciprocal of the original slope.
The original slope is .
The negative reciprocal of the original slope is:
Example Question #1 : How To Find The Slope Of A Perpendicular Line
What is the slope of a line perpendicular to ?
The equation is a vertical line on the coordinate plane. Any line perpendicular to a vertical line is a horizontal line. Horizontal lines have slopes of zero.
The correct answer is .
Example Question #11 : Perpendicular Lines
Assume the points and form a line. A perpendicular line is drawn to intersect this line. What is the slope of the perpendicular line?
Write the slope formula and find the slope of the first line.
The slope of the perpendicular line is the negative reciprocal of the original slope.
Therefore, the slope of the perpendicular line is .
Example Question #1 : How To Find The Slope Of A Perpendicular Line
A line goes through the following and .
Find the slope of a line perpendicular to the line given.
The slope of a line perpendicular is the negative reciprocal of the given line.
Since the given slope is calculated as , then the slope of the perpendicular line would be .
Example Question #1 : How To Find Out If Lines Are Perpendicular
Which of the following lines is perpendicular to the line
The slope of the given line is 3. The slope of a perpendicular line is the negative inverse of the given line. In this case, that is equal to . Therefore, the correct answer is:
Example Question #2 : How To Find Out If Lines Are Perpendicular
Given the equation of a line:
Which equation given below is perpendicular to the given line?
When looking at the equation of the given line, we know that the slope is and the y-intercept is . Any line perpendicular to the given line will create a 90 degree angle with the given line.
Now, there are INFINITE lines perpendicular to the given line, all with different y-intercepts. So in other words, the line we are looking for will have no dependence on the y-intercept, as any y-intercept will do. What we do care about is the slope of the line.
The slope of any line perpendicular to a given line has a negative reciprocal of the slope. So for this problem:
The only line that has this slope is
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