All SAT Math Resources
Example Questions
Example Question #1 : How To Find Out If Lines Are Perpendicular
Line is given by .
Which of the following is perpendicular to ?
Putting the equation of the line into slope-intercept form, we get
The slope of line , therefore, is .
In order for a line to be perpendicular to the given line, it must have a slope that is the negative reciprocal of line g's slope.
The slope of any given line perpendicular to line g must be when written in slope-intercept form. In other words, the equation of the perpendicular line must be where k is any constant.
Written in standard form, the equation of this perpendicular line must be
Therefore, the most appropriate answer is
Example Question #2 : How To Find Out If Lines Are Perpendicular
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 is .
Which of the following is a true statement?
Line A and Line C are perpendicular to each other, but Line B is perpendicular to neither Line A nor Line C.
None of the statements in the other choices is true.
Line A and Line B are perpendicular to each other, but Line C is perpendicular to neither Line A nor Line B.
No two of Line A, Line B, and Line C are perpendicular to each other.
Line B and Line C are perpendicular to each other, but Line A is perpendicular to neither Line B nor Line C.
No two of Line A, Line B, and Line C are perpendicular to each other.
Two lines are perpendicular if and only if the product of their slopes is . Therefore, we need to find the slopes of all three lines.Rewrite the equation for each line in its slope-intercept form , where is the slope of the line.
Line A:
is already in this form. The slope of Line A is the coefficient of , which is 3.
Line B:
Isolate by working the same operations on both sides:
The slope of Line B is the coefficient of , which is 3.
Line C:
The slope of Line C is the coefficient of , which is 3.
All three lines have slope 3, so the product of the slopes of any two of the lines is . Therefore, no two of the lines are perpendicular.
Example Question #1 : How To Find Out If Lines Are Perpendicular
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?
Line A and Line C are perpendicular to each other, but Line B is perpendicular to neither Line A nor Line C.
Line A and Line B are perpendicular to each other, but Line C is perpendicular to neither Line A nor Line B.
Line B and Line C are perpendicular to each other, but Line A is perpendicular to neither Line B nor Line C.
None of the statements in the other choices is true.
No two of Line A, Line B, and Line C are perpendicular to each other.
Line A and Line B are perpendicular to each other, but Line C is perpendicular to neither Line A nor Line B.
Two lines are perpendicular if and only if the product of their slopes is . Therefore, we need to find the slopes of all three lines.
Rewrite the equation for each line in its slope-intercept form , where is the slope of the line.
Line A:
Isolate by working the same operations on both sides:
The slope of Line A is the coefficient of , which is .
Take the same steps with the equations of the other two lines:
Line B:
The slope of Line B is
Line C:
The slope of Line C is .
The product of the slopes of Lines A and B is , so these two lines are perpendicular.
The product of the slopes of Lines A and C is , so these two lines are not perpendicular.
The product of the slopes of Lines B and C is , so these two lines are not perpendicular.
Example Question #7 : How To Find Out If Lines Are Perpendicular
Given: Lines A, B, and C on the coordinate plane, as follows:
Line A has intercepts and .
Line B has intercepts and .
Line C has intercepts and .
Which of the following statements is true?
No two of Line A, Line B, and Line C are perpendicular to each other.
Line A and Line B are perpendicular to each other, but Line C is perpendicular to neither Line A nor Line B.
Line B and Line C are perpendicular to each other, but Line A is perpendicular to neither Line B nor Line C.
Line A and Line C are perpendicular to each other, but Line B is perpendicular to neither Line A nor Line C.
None of the statements in the other choices is true.
No two of Line A, Line B, and Line C are perpendicular to each other.
The slope of each line, given the coordinates of two points through which they pass, can be calculated by substituting the point coordinates into the slope formula
.
Line A:
Setting and substituting:
Line B:
Setting and substituting:
Line C:
Setting and substituting:
The product of the slopes of Line A and Line B is , as is the product of the slopes of Line C and Line B; Since neither product is equal to , neither pair of lines is perpendicular. Also, the slopes of Line A and Line C are equal, so the lines are parallel, not perpendicular.
Example Question #1 : Perpendicular Lines
Which of the following lines is perpendicular to
The line which is perpendicular has a slope which is the negative inverse of the slope of the original line.
Example Question #81 : Lines
Lines P and Q are parallel. Find the value of .
Since these are complementary angles, we can set up the following equation.
Now we will use the quadratic formula to solve for .
Note, however, that the measure of an angle cannot be negative, so is not a viable answer. The correct answer, then, is
Example Question #1 : Other Lines
In the xy -plane, line l is given by the equation 2x - 3y = 5. If line l passes through the point (a ,1), what is the value of a ?
The equation of line l relates x -values and y -values that lie along the line. The question is asking for the x -value of a point on the line whose y -value is 1, so we are looking for the x -value on the line when the y-value is 1. In the equation of the line, plug 1 in for y and solve for x:
2x - 3(1) = 5
2x - 3 = 5
2x = 8
x = 4. So the missing x-value on line l is 4.
Example Question #2 : Other Lines
The equation of a line is: 2x + 9y = 71
Which of these points is on that line?
(2,7)
(-2,7)
(4,7)
(4,-7)
(-4,7)
(4,7)
Test the difference combinations out starting with the most repeated number. In this case, y = 7 appears most often in the answers. Plug in y=7 and solve for x. If the answer does not appear on the list, solve for the next most common coordinate.
2(x) + 9(7) = 71
2x + 63 = 71
2x = 8
x = 4
Therefore the answer is (4, 7)
Example Question #3 : Points And Distance Formula
Which of the following lines contains the point (8, 9)?
In order to find out which of these lines is correct, we simply plug in the values and into each equation and see if it balances.
The only one for which this will work is
Example Question #471 : Geometry
Which point lies on this line?
Test the coordinates to find the ordered pair that makes the equation of the line true: