GMAT Math : Geometry

Study concepts, example questions & explanations for GMAT Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #15 : Lines

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 

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 

Possible Answers:

Correct answer:

Explanation:

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 

Example Question #1 : Understanding Rays

Lines

Refer to the above figure.  and which of the following are opposite rays?

Possible Answers:

Correct answer:

Explanation:

Opposite rays begin at the same endpoint; their directions are opposite each other. Since  has endpoint , we are looking for the ray that has endpoint  and goes in the opposite direction - this ray is  .

Example Question #401 : Geometry

Lines

Refer to the above figure. Which of the following is another name for  ?

Possible Answers:

None of the other choices is correct.

Correct answer:

Explanation:

A ray can be named with two letters, the first of which must be its endpoint and the second of which can be any other point on the ray.

 has endpoint . The only other marked point on the ray is , so the correct choice is .

Example Question #1 : Understanding Rays

A ray starts at the point    and has a positive slope of  .  In which quadrants does some part of the ray lie?

Possible Answers:

Correct answer:

Explanation:

A ray starts at a single point and then continues in a straight line infinitely in some direction. The given ray starts at the point  ,  which is in quadrant  , so we immediately know this must be included in the answer. The ray has a positive slope of  ,  which means the next point is  ,  followed by  ,  ,  ,  ,  and so on. By plotting these points we can visualize that the ray starts in quadrant  ,  crosses through quadrant  ,  and then continues infinitely into quadrant  ,  without ever crossing through any part of quadrant  .  The answer, therefore, is the following three quadrants:

Example Question #3 : Understanding Rays

Thingy

In the above figure, which two rays have as their union  ?

Possible Answers:

 and 

 and  

 and  

 and  

 and  

Correct answer:

 and 

Explanation:

An angle, by definition, is the union of two rays with the same endpoint. Their common endpoint is the vertex of the angle, which is always named by the middle letter of a three-letter angle name. Therefore, we are looking for two rays with endpoint . Since the first letter of the name of a ray is always its endpoint, we are looking for two rays with  as the first letter in their names. This makes  and  the correct choice.

Example Question #1 : Understanding Rays

Thingy

In the above figure, give the intersection of  and .

Possible Answers:

Correct answer:

Explanation:

 can be seen to be completely contained in  - that is, . The intersection of a set and its subset is the subset, so the correct response is .

Example Question #6 : Understanding Rays

Thingy

In the above figure, give the intersection of  and .

Possible Answers:

Correct answer:

Explanation:

The diagram below show  and  in red and green, respectively:

Thingy_x

The intersection of  and  is the set of points they have in common, which can be seen to be the portion of the line with endpoints  and . This figure is the line segment .

Example Question #7 : Understanding Rays

Thingy

Which of the following could be another name for  in the above figure?

I) 

II) 

III)

Possible Answers:

II only 

I and III only

I only

I, II, and III

I and II only

Correct answer:

I only

Explanation:

A ray is named after its endpoint and any other point on the ray, in that order. Since  is the first letter in the name ,  is its endpoint, and any other name for the ray must begin with ; this allows us to eliminate . Also,  is eliminated, since a ray is named after two, not three, points.  is a correct choice, since the first letter in this name is endpoint , and the second letter names a point on this ray.

Example Question #4 : Understanding Rays

Thingy

In the above diagram, let  and  be the midpoints of  and , respectively, and  and  be the midpoints of  and , respectively. Which of the following is not a valid alternative name for  ?

Possible Answers:

Each of the other choices gives a valid alternative name for .

Correct answer:

Explanation:

Below is the diagram with the points , and , as described, shown in green. Also, , the ray that has endpoint  and passes through , is marked in red.

Thingy_x

The ray also passes through , and , so  , and  are also valid names for the ray. However, the ray does not pass through , so  is not a valid name for the ray.  is the correct choice.

Tired of practice problems?

Try live online GMAT prep today.

1-on-1 Tutoring
Live Online Class
1-on-1 + Class
Learning Tools by Varsity Tutors