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Example Questions
Example Question #411 : Geometry
Which of the following are parallel to the line ?
A.Â
B.Â
C.Â
D.Â
E.Â
D & E
A, B, & C
A & D
C & D
None of the given answers
A & D
In order for two lines to be parallel, they must have the same slope and different y-intercepts. In slope-intercept form, the slope of the coefficient of our  value.Â
We want to find lines that have a slope of . The two answers that share this slope with the given equation areÂ
 andÂ
, which correspond with answers A and D.Â
Example Question #31 : Coordinate Geometry
Given lines on the coordinate plane as follows:
Line A has equationÂ
Line B has equationÂ
Line C has equationÂ
Which of the following is a true statement?Â
Line A, Line B, and Line C are parallel to one other.
No two of Line A, Line B, and Line C are parallel to each other.
Line A and Line B are parallel to each other, but Line C is parallel to neither Line A nor Line B.
Line B and Line C are parallel to each other, but Line A is parallel to neither Line B nor Line C.
Line A and Line C are parallel to each other, but Line B is parallel to neither Line A nor Line C.
No two of Line A, Line B, and Line C are parallel to each other.
Two lines are parallel if and only if they have the same slope. Therefore, we must find the slope of each line. We do this by rewriting each equation in slope-intercept form , withÂ
-coefficientÂ
 being the slope of the line.
In each case, solve for  by isolating this variable on the left side.
Line A:
The slope of Line A is the -coefficientÂ
.
Â
Â
Line B:Â
The slope of Line Bis the -coefficientÂ
.
Â
Line C:Â
The slope of Line C is the -coefficientÂ
.
Â
No two of the given lines have the same slope, so no two are parallel.
Example Question #33 : Parallel Lines
Given Lines A, B, and C on the coordinate plane as follows:
The equation of Line A is .
The equation of Line B is .
The equation of Line C is .
Which of the following is a true statement?
No two of Line A, Line B, and Line C are parallel to each other.
Line A and Line C are parallel to each other, but Line B is parallel to neither Line A nor Line C.
Line A, Line B, and Line C are parallel to one other.
Line A and Line B are parallel to each other, but Line C is parallel to neither Line A nor Line B.
Line B and Line C are parallel to each other, but Line A is parallel to neither Line B nor Line C.
Line A, Line B, and Line C are parallel to one other.
Two lines are parallel if and only if they have the same slope. Therefore, we must find the slope of each line. We do this by rewriting each equation in slope-intercept form , withÂ
-coefficientÂ
 being the slope of the line.
In each case, solve for  by isolating this variable on the left side.
Line A:
.
This equation is already in slope-intercept form. The slope of Line A is the -coefficientÂ
.
Line B:
The slope of Line B is the -coefficientÂ
.
Line C:
The slope of Line C is the -coefficientÂ
.
Â
In each case, the slope is . The three lines, having the same slope, are all parallel to one another.
Example Question #34 : Parallel Lines
Given Lines A, B, and C on the coordinate plane as follows:
Line A has intercepts  andÂ
.
Line B has intercepts  andÂ
.
Line C has intercepts  andÂ
.
Which statement is true?
Lines A and BÂ are parallel to each other, but Line CÂ is parallel to neither line.
Lines A, B, and C are all parallel to one another.
Lines A and C are parallel to each other, but Line B is parallel to neither line.
Lines B and C are parallel to each other, but Line A is parallel to neither line.
No two of Lines A, B, and C are parallel.Â
Lines A and C are parallel to each other, but Line B is parallel to neither line.
Two lines are parallel if an only if their slopes are equal. The slope of a line with -interceptÂ
 and
-interceptÂ
 can be determined using the formula
.
Calculate the slope of Line A by setting :
Calculate the slope of Line B by setting :
Calculate the slope of Line B by setting :
Lines A and C have the same slope and are parallel; Line B has a different slope and is not parallel to the other two.
Example Question #2 : How To Find Out If Lines Are Parallel
Which of the following lines is parallel to:
Â
First write the equation in slope intercept form. Add  to both sides to get
. Now divide both sides by
 to get
. The slope of this line is
, so any line that also has a slope of
 would be parallel to it. The correct answer is Â
.
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