Coordinate Geometry
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SSAT Upper Level Quantitative › Coordinate Geometry
What line is perpendicular to and passes through
?
Explanation
Convert the given equation to slope-intercept form.
The slope of this line is . The slope of the line perpendicular to this one will have a slope equal to the negative reciprocal.
The perpendicular slope is .
Plug the new slope and the given point into the slope-intercept form to find the y-intercept.
So the equation of the perpendicular line is .
Consider the lines described by the following two equations:
4y = 3x2
3y = 4x2
Find the vertical distance between the two lines at the points where x = 6.
36
21
12
44
48
Explanation
Since the vertical coordinates of each point are given by y, solve each equation for y and plug in 6 for x, as follows:

Taking the difference of the resulting y -values give the vertical distance between the points (6,27) and (6,48), which is 21.
Which of the following lines is parallel with the line ?
Explanation
Parallel lines have the same slope. The slope of a line in slope-intercept form is the value of
. So, the slope of the line
is
. That means that for the two lines to be parallel, the slope of the second line must also be
.
Find the slope of the line perpendicular to the line that has the equation .
Explanation
Perpendicular lines have slopes that are negative reciprocals of each other. In other words, change the sign and flip the fraction around.
Consider the lines described by the following two equations:
4y = 3x2
3y = 4x2
Find the vertical distance between the two lines at the points where x = 6.
36
21
12
44
48
Explanation
Since the vertical coordinates of each point are given by y, solve each equation for y and plug in 6 for x, as follows:

Taking the difference of the resulting y -values give the vertical distance between the points (6,27) and (6,48), which is 21.
What is the slope of a line which passes through coordinates and
?
Explanation
Slope is found by dividing the difference in the -coordinates by the difference in the
-coordinates.
Find the equation of a line that goes through the point and is parallel to the line with the equation
.
Explanation
For lines to be parallel, they must have the same slope. The slope of the line we are looking for then must be .
The point that's given in the equation is also the y-intercept.
Using these two pieces of information, we know that the equation for the line must be
What line is perpendicular to and passes through
?
Explanation
Convert the given equation to slope-intercept form.
The slope of this line is . The slope of the line perpendicular to this one will have a slope equal to the negative reciprocal.
The perpendicular slope is .
Plug the new slope and the given point into the slope-intercept form to find the y-intercept.
So the equation of the perpendicular line is .
Which of the following lines is parallel to the line ?
Explanation
For two lines to be parallel, their slopes must be the same. Thus, the line that is parallel to the given one must also have a slope of .
What is the slope of a line which passes through coordinates and
?
Explanation
Slope is found by dividing the difference in the -coordinates by the difference in the
-coordinates.