How can you determine if two lines are perpendicular?
2007-08-15 16:35:13 · 11 answers · asked by ? 2 in Science & Mathematics ➔ Mathematics
if their slope is opposite reciprocal of each other
for example:
if one slope is 2/5 then the othe slope must be - 5/2
the ther way to tell if two lines are perpendicular to each other is by multiply thier slope together. If the answer is -1, then the two lines are perpendicular to each other.
2/5 * -5/2 = -1
2007-08-15 16:41:35 · answer #1 · answered by 7 · 0⤊ 0⤋
The have to have an inverse slope and the signs are opposites. Example; 2x+3=7 and -1/2x+4=10. They will be perpendicular because the 2 and the 1/2 are inverses. Note, one of them must be negative and the other positive(it doesn't matter which one). Always get the linear equation in the form of y=mx+b. It is the m you are interested in. Also, it the m is the same in both equations, then the lines are parallel.
2007-08-15 23:45:26 · answer #2 · answered by Ed S 4 · 0⤊ 0⤋
In order for two lines to be perpendicular, they must have slopes that are negative reciprocals of each other. This means that the number would be flipped and one of them must be a negative. Also, if you multiply the two numbers their product will equal -1.
For example:
7/3 and -3/7 would be perpendicular slopes because
1.) they are negative recipricals. and
2.) 7/3 * -3/7 = -1
Hope this helps...
Demonsthenes
2007-08-15 23:58:05 · answer #3 · answered by Demonsthenes 2 · 0⤊ 0⤋
In simple algebra, as in dealing with simple lines that can be expressed as y=mx + b, where m is the slope and b is the offset, if line 1's slope is the opposite and reciprocal of line 2's slope.
for example,
line 1 = 3x - 5
line 2 = -1/3x +2
they are perpendicular cuz the slopes are 3 and -1/3
line 1 = 3x - 5
line 2 = +1/3x + 5
they are not perpendicular cuz the slopes are reciprocals but the signs match.
2007-08-15 23:42:11 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Okay you need to find the slope of each of the lines.
m = (y2- y1)
-----------
(x2- x1)
ex you have the points (-3, 4) and (-1, 6)
m = (6-4)
-------
(-1- -3)
so you have
m = 2/ 2 = 1
If they are parallel they will have the same slopes.
If they are perpendicular, they will be the negative reciprocals of each other. ex.. say line a has slope 3/4 and line b has slope -4/3 then these two lines are perpendicular.
2007-08-16 00:15:25 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Two lines are perpendicular if their slopes are the negative reciprocals of each other. If they are then they multiply to -1.
The only exception is if one line is horizontal and the other is vertical. They are also perpendicular.
2007-08-15 23:39:51 · answer #6 · answered by Northstar 7 · 1⤊ 0⤋
If you are given the equations of the lines, you can do a simple test with their slopes. The product of the slopes of perpendicular lines = -1, so see if the products do that!
2007-08-15 23:40:36 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Perpendicular lines have negative reciprocal slopes. So if you multiply the both slopes together and the answer is -1 then they are perpendicular.
2007-08-15 23:40:29 · answer #8 · answered by Edgard L 2 · 0⤊ 0⤋
If they meet at a 90 degree angle. like the angle on a capital L. Perfectly square.
2007-08-15 23:39:10 · answer #9 · answered by Anonymous · 0⤊ 0⤋
when the two lines are at 90 degree angles It is an upside down "T" upside down remember and both of those angles = 90 degrees
2007-08-15 23:42:27 · answer #10 · answered by Promoqueen in CA 3 · 0⤊ 0⤋