Welcome to Westonci.ca, your one-stop destination for finding answers to all your questions. Join our expert community now! Experience the convenience of finding accurate answers to your questions from knowledgeable professionals on our platform. Get quick and reliable solutions to your questions from a community of experienced experts on our platform.

Select the correct answer.

The coordinates of point J are [tex]\((-7,2)\)[/tex], and the midpoint of [tex]\(JK\)[/tex] is at [tex]\(L(3, 5)\)[/tex]. What are the coordinates of point K?

A. [tex]\((-1, 12)\)[/tex]
B. [tex]\((8, 3)\)[/tex]
C. [tex]\((4, -2)\)[/tex]
D. [tex]\((13, 8)\)[/tex]


Sagot :

Let's solve this step-by-step.

Given:
- Coordinates of point J: [tex]\((-7, 2)\)[/tex]
- Coordinates of the midpoint L: [tex]\((3, 5)\)[/tex]

We need to find the coordinates of point K. To do that, we use the midpoint formula. The midpoint [tex]\(L\)[/tex] of a line segment between two points [tex]\(J\)[/tex] [tex]\((x_1, y_1)\)[/tex] and [tex]\(K\)[/tex] [tex]\((x_2, y_2)\)[/tex] is given by:
[tex]\[ L\left(\frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2}\right) \][/tex]

We know the coordinates of [tex]\(L\)[/tex], [tex]\(J\)[/tex], and need to find [tex]\(K\)[/tex].

First, let's set up the equations using the midpoint coordinates [tex]\((3, 5)\)[/tex]:
1. [tex]\(\frac{x_1 + x_2}{2} = 3\)[/tex]
2. [tex]\(\frac{y_1 + y_2}{2} = 5\)[/tex]

We can plug in the coordinates of [tex]\(J\)[/tex] [tex]\((-7, 2)\)[/tex]:

1. [tex]\(\frac{-7 + x_2}{2} = 3\)[/tex]
2. [tex]\(\frac{2 + y_2}{2} = 5\)[/tex]

Next, solve each of these equations for [tex]\(x_2\)[/tex] and [tex]\(y_2\)[/tex]:

1. Multiply both sides by 2:
[tex]\[ -7 + x_2 = 6 \][/tex]
Add 7 to both sides:
[tex]\[ x_2 = 13 \][/tex]

2. Multiply both sides by 2:
[tex]\[ 2 + y_2 = 10 \][/tex]
Subtract 2 from both sides:
[tex]\[ y_2 = 8 \][/tex]

Therefore, the coordinates of point [tex]\(K\)[/tex] are [tex]\((13, 8)\)[/tex].

Hence, the correct answer is:
- D. [tex]\((13, 8)\)[/tex]