# GMAT Math : Calculating whether lines are perpendicular

## Example Questions

2 Next →

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

Which of the following lines is perpendicular to

Not enough information provided.

Explanation:

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

Two of the answers are correct.

Two of the answers are correct.

Explanation:

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 ?

Not enough information provided

Explanation:

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

Explanation:

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 ?

None of the lines is perpendicular

Two lines are perpendicular

Two lines are perpendicular

Explanation:

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