### All GMAT Math Resources

## Example Questions

### Example Question #11 : Calculating Whether Lines Are Perpendicular

Which of the following lines is perpendicular to ?

**Possible Answers:**

Not enough information provided.

**Correct answer:**

Given a line defined by the equation with a slope of , any line perpendicular to would have a slope that is the negative reciprocal of , . Given our equation , we know that and that .

The only answer choice with this slope is .

### Example Question #12 : Calculating Whether Lines Are Perpendicular

Which of the following lines is perpendicular to

**Possible Answers:**

Two of the answers are correct.

**Correct answer:**

Two of the answers are correct.

Given a line defined by the equation with a slope of , any line perpendicular to would have a slope that is the negative reciprocal of , . Given our equation , we know that and that .

There are two answer choices with this slope, and .

### Example Question #13 : Calculating Whether Lines Are Perpendicular

A given line is defined by the equation . Which of the following lines would be perpendicular to line ?

**Possible Answers:**

Not enough information provided

**Correct answer:**

For any line with an equation and slope , a line that is perpendicular to must have a slope of , or the negative reciprocal of . Given , we know that and therefore know that .

Only one equation above has a slope of : .

### Example Question #14 : Calculating Whether Lines Are Perpendicular

What is the slope of a line that is perpendicular to

**Possible Answers:**

**Correct answer:**

For any line with an equation and slope , a line that is perpendicular to must have a slope of , or the negative reciprocal of . Given the equation , we know that and therefore know that .

### Example Question #15 : Calculating Whether Lines Are Perpendicular

Which of the following lines is perpendicular to ?

**Possible Answers:**

None of the lines is perpendicular

Two lines are perpendicular

**Correct answer:**

Two lines are perpendicular

For any line with an equation and slope , a line that is perpendicular to must have a slope of , or the negative reciprocal of . Given the equation , we know that and therefore know that .

Given a slope of , we know that there are two solutions provided: and .

### Example Question #16 : Calculating Whether Lines Are Perpendicular

What is the slope of a line perpendicular to that of

**Possible Answers:**

**Correct answer:**

First, we need to rearrange the equation into slope-intercept form. .

Therefore, the slope of this line equals Perpendicular lines have slope that are the opposite reciprocal, or