GMAT Math : Coordinate Geometry

Study concepts, example questions & explanations for GMAT Math

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Example Questions

Example Question #1 : Calculating The Endpoints Of A Line Segment

A line segment has its midpoint at  and an endpoint at .  What are the coordinates of the other endpoint?

Possible Answers:

Correct answer:

Explanation:

Because we are given the midpoint and one of the endpoints, we know the x coordinate of the other endpoint will be the same distance away from the midpoint in the x direction, and the y coordinate of the other endpoint will be the same distance away from the midpoint in the y direction. Given two endpoints of the form:

The midpoint of these two endpoints has the coordinates:

Plugging in values for the given midpoint and one of the endpoints, which we can see is  because it lies to the right of the midpoint, we can solve for the other endpoint as follows:

So the other endpoint has the coordinates  

Example Question #2 : Calculating The Endpoints Of A Line Segment

Consider segment  with endpoint  at . If the midpoint of  can be found at , what are the coordinates of point ?

 

Possible Answers:

Correct answer:

Explanation:

Recall midpoint formula:

In this case we have (x'y') and one of our other (x,y) points.

Plug and chug:

If you make this into two equations and solve you get the following.

 

 

 

Example Question #1 : Calculating The Length Of A Line With Distance Formula

A line segement on the coordinate plane has endpoints  and . Which of the following expressions is equal to the length of the segment?

Possible Answers:

Correct answer:

Explanation:

Apply the distance formula, setting

:

Example Question #2 : Calculating The Length Of A Line With Distance Formula

What is distance between  and ?

Possible Answers:

Correct answer:

Explanation:

Example Question #1 : Calculating The Length Of A Line With Distance Formula

What is the distance between the points  and ?

Possible Answers:

2\sqrt{5}

Correct answer:

Explanation:

Let's plug our coordinates into the distance formula.

\sqrt{(2-7)^{2}+(5-17)^{2}}= \sqrt{(-5)^{2}+(-12)^{2}} = \sqrt{25+144}= \sqrt{169} = 13

Example Question #1 : Calculating The Length Of A Line With Distance Formula

What is the distance between the points  and ?

Possible Answers:

2\sqrt{5}

3\sqrt{3}

Correct answer:

2\sqrt{5}

Explanation:

We need to use the distance formula to calculate the distance between these two points.

\sqrt{(1-5)^{2}+(4-2)^{2}} = \sqrt{(-4)^{2}+(2)^{2}} =\sqrt{20}=\sqrt{4}\sqrt{5}=2\sqrt{5}

Example Question #5 : Calculating The Length Of A Line With Distance Formula

Consider segment  which passes through the points  and .

Find the length of segment .

Possible Answers:

Correct answer:

Explanation:

This question requires careful application of distance formula, which is really a modified form of Pythagorean theorem.

Plug in everthing and solve:

So our answer is 156.6

Example Question #6 : Calculating The Length Of A Line With Distance Formula

What is the length of a line segment that starts at the point    and ends at the point    ?

Possible Answers:

Correct answer:

Explanation:

Using the distance formula for the length of a line between two points, we can plug in the given values and determine the length of the line segment by calculating the distance between the two points:

Example Question #1 : Tangent Lines

Determine the equation of the line tangent to the curve    at the point    ?

Possible Answers:

Correct answer:

Explanation:

To find the equation of a line tangent to a curve at a certain point, we first need to find the slope of the curve at that point. To find the slope of a function at any point, we need its derivative:

Now we can plug in the x value of the given point to find the slope of the function, and therefore the slope of tangent line, at that point:

Now that we have our slope, we can simply plug this value in with the given point to solve for the y intercept of the tangent line:

We have calculated the slope of the tangent line and its y intercept, so the equation for the line tangent to the curve    at the point    in standard form is:

Example Question #2 : Tangent Lines

Determine the equation of the line tangent to the following curve at the point  .

Possible Answers:

Correct answer:

Explanation:

First we find the slope of the tangent line by taking the derivative of the function and plugging in the -value of the point where we want to know the slope:

Now that we know the slope of the tangent line, we can plug it into the equation for a line along with the coordinates of the given point in order to calculate the -intercept:

We now have  and , so we can write the equation of the tangent line:

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