Intermediate Geometry : Parallel Lines

Study concepts, example questions & explanations for Intermediate Geometry

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Example Questions

Example Question #21 : Parallel Lines

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The slope of line CD is 4x, and Angle 1 and Angle 5 are congruent. What is the slope of line AB and why?

Possible Answers:

4x, because of Corresponding Angles Theorem

(1/4)x, because of the Corresponding Angle Theorem

4x, because of Alternate Interior Angles Theorem

4x, because of the Vertical Angle Theorem

There is not enough information to determine

Correct answer:

4x, because of Corresponding Angles Theorem

Explanation:

Parallel lines have the same slope. If Angles 1 and 5 are congruent, then lines AB and CD have the same slope (4x) based on the Congruent Angles Theorem. 

Example Question #1 : How To Find The Slope Of Parallel Lines

Any line that is parallel to  must have a slope of what?

Possible Answers:

Correct answer:

Explanation:

Two lines are parallel if and only if they have the same slope. 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 each side of the equation, giving us . Next, we divide both sides by , giving us . We can now see that the slope is .

Example Question #191 : Coordinate Geometry

Suppose the equation of the first line is .  What must be the value of  to make the second equation  parallel to the first line?

Possible Answers:

Correct answer:

Explanation:

Rewrite both equations so that they are in slope-intercept form, .

For the first equation:

The slope of the first line is .  

Rewrite the second equation in slope-intercept form:

The value of  must be equal to three to be parallel. Solve for .

Example Question #2 : How To Find The Slope Of Parallel Lines

If the equation of one line is , what must be the slope of another line so that both lines are parallel to each other?

Possible Answers:

Correct answer:

Explanation:

Rewrite the equation of the first line in slope-intercept form, .

The value of the slope, , can be seen as . For another line to be parallel to this line, their slopes must be the same.

Example Question #6 : How To Find The Slope Of Parallel Lines

Find a line parallel to the line with the equation:

 

Possible Answers:

Correct answer:

Explanation:

For two lines to be parallel, they must have the same slope. For a line in , or slope intercept form,  corresponds to the slope of the line.

For the given line, . A line that is parallel must also then have the same slope. 

Only the following line has the same slope:

Example Question #7 : How To Find The Slope Of Parallel Lines

Find a line parallel to the line with the equation:

Possible Answers:

Correct answer:

Explanation:

For two lines to be parallel, they must have the same slope. For a line in , or slope intercept form,  corresponds to the slope of the line.

For the given line, . A line that is parallel must also then have the same slope. 

Only the following line has the same slope:

Example Question #8 : How To Find The Slope Of Parallel Lines

Find a line parallel to the line with the equation:

Possible Answers:

Correct answer:

Explanation:

For two lines to be parallel, they must have the same slope. For a line in , or slope intercept form,  corresponds to the slope of the line.

For the given line, . A line that is parallel must also then have the same slope.

Only the following line has the same slope:

Example Question #9 : How To Find The Slope Of Parallel Lines

Find a line parallel to the line with the equation: 

Possible Answers:

Correct answer:

Explanation:

For two lines to be parallel, they must have the same slope. For a line in , or slope intercept form,  corresponds to the slope of the line.

For the given line, . A line that is parallel must also then have the same slope. 

Only the following line has the same slope:

Example Question #1 : How To Find The Equation Of A Parallel Line

What is the equation of a line that is parallel to the line \small y=\frac{1}{2}x+3 and includes the point ?

Possible Answers:

\small y=\frac{1}{2}x+6

\small y=\frac{1}{2}x

\small y=2x-6

\small y=-2x+10

Correct answer:

\small y=\frac{1}{2}x

Explanation:

The line parallel to \small y=\frac{1}{2}x+3 must have a slope of \frac{1}{2}, giving us the equation \small y=\frac{1}{2}x+b. To solve for b, we can substitute the values for y and x.

\small 2=(\frac{1}{2})(4)+b 

\small 2=2+b

\small b=0

Therefore, the equation of the line is \small y=\frac{1}{2}x.

Example Question #1 : How To Find The Equation Of A Parallel Line

Suppose a line  . What is the equation of a parallel line that intersects point ?

Possible Answers:

Correct answer:

Explanation:

A line parallel to  must have a slope of two. Given the point  and the slope, use the slope-intercept formula to determine the -intercept by plugging in the values of the point and solving for :

Plug the slope and the -intercept into the slope-intercept formula:

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