Distance Formula

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ACT Math › Distance Formula

Questions 1 - 10
1

What is the distance between (1,5) and (6,17)?

Explanation

Let P_{1}=(1,5) and P_{2}=(6,17)

So we use the distance formula d =\sqrt{(x_{2} - x_{1})^2+(y_{2} - y_{1})^2}

and evaluate it using the given points:

d=\sqrt{(6-1)^2+(17 - 5)^2}= \sqrt{(5)^2+(12)^2}=13

2

What is the distance between (1,5) and (6,17)?

Explanation

Let P_{1}=(1,5) and P_{2}=(6,17)

So we use the distance formula d =\sqrt{(x_{2} - x_{1})^2+(y_{2} - y_{1})^2}

and evaluate it using the given points:

d=\sqrt{(6-1)^2+(17 - 5)^2}= \sqrt{(5)^2+(12)^2}=13

3

What is the distance of the line

Between and ?

Round to the nearest hundredth.

Explanation

What is the distance of the line

Between and ?

To calculate this, you need to know the points for these two values. To find these, substitute in for the two values of given:

Likewise, do the same for :

Now, this means that you have two points:

and

The distance formulat between two points is:

For our data, this is:

This is:

or approximately

4

What is the distance of the line

Between and ?

Round to the nearest hundredth.

Explanation

What is the distance of the line

Between and ?

To calculate this, you need to know the points for these two values. To find these, substitute in for the two values of given:

Likewise, do the same for :

Now, this means that you have two points:

and

The distance formulat between two points is:

For our data, this is:

This is:

or approximately

5

What is the distance between the x and y intercepts of:

Round to the nearest hundredth.

Explanation

In order to find the distance between these two points, we first need the points! To find them, substitute in for x and y. Thus, for each you get:

Thus, the two points are:

and

The distance formulat between two points is:

For your data, this is very simply:

or

6

What is the distance between the x and y intercepts of:

Round to the nearest hundredth.

Explanation

In order to find the distance between these two points, we first need the points! To find them, substitute in for x and y. Thus, for each you get:

Thus, the two points are:

and

The distance formulat between two points is:

For your data, this is very simply:

or

7

Coordinates

What is the slope of the line between points \dpi{100} \small A and \dpi{100} \small B?

\frac{5}{4}

\frac{-5}{4}

\frac{5}{2}

5

-4

Explanation

The slope of the line between points \dpi{100} \small A and \dpi{100} \small B is \frac{5}{4}. Point \dpi{100} \small A is at \dpi{100} \small (-2,-3). Point \dpi{100} \small B is at \dpi{100} \small (2,2). Putting these points into the slope formula, we have \frac{-3-2}{-2-2}=\frac{-5}{-4}=\frac{5}{4}.

8

Coordinates

What is the slope of the line between points \dpi{100} \small A and \dpi{100} \small B?

\frac{5}{4}

\frac{-5}{4}

\frac{5}{2}

5

-4

Explanation

The slope of the line between points \dpi{100} \small A and \dpi{100} \small B is \frac{5}{4}. Point \dpi{100} \small A is at \dpi{100} \small (-2,-3). Point \dpi{100} \small B is at \dpi{100} \small (2,2). Putting these points into the slope formula, we have \frac{-3-2}{-2-2}=\frac{-5}{-4}=\frac{5}{4}.

9

What is the area of a square with a diagonal that has endpoints at (4, **–**1) and (2, **–**5)?

5

10

20

25

100

Explanation

First, we need to find the length of the diagonal. In order to do that, we will use the distance formula:

Actmath_29_372_q6_1

Actmath_29_372_q6_2

Now that we have the length of the diagonal, we can find the length of the side of a square. The diagonal of a square makes a 45/45/90 right triangle with the sides of the square, which we shall call s. Remember that all sides of a square are equal in length.

Because this is a 45/45/90, the length of the hypotenuse is equal to the length of the side multiplied by the square root of 2

Actmath_29_372_q6_3

Actmath_29_372_q6_4_copy

The area of the square is equal to s2, which is 10.

10

What is the distance, in coordinate units, between the points (-2,6) and (5,-2) in the standard (x,y) coordinate plane?

\sqrt{113}

\sqrt{15}

15

113

\sqrt{7}

Explanation

The distance formula is \sqrt{((x_{1}-x_{2})^{2}+(y_{1}-y_{2})^{2})}=d, where d = distance.

Plugging in our values, we get

d=\sqrt{((5-(-2))^{2}+(6-(-2))^{2}}=\sqrt{7^{2}+8^{2}}=\sqrt{49+64}=\sqrt{113}

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