Select the correct answer.

Grady's father is building a 15-meter fence with the start of the fence at coordinates [tex]\((8,5)\)[/tex] and the midpoint of the fence at coordinates [tex]\((3.5,-1)\)[/tex]. What are the coordinates of the other end of the fence?

A. [tex]\((-1,-7)\)[/tex]
B. [tex]\((-15,-3)\)[/tex]
C. [tex]\((12,6)\)[/tex]
D. [tex]\((2,-9)\)[/tex]



Answer :

To find the coordinates of the other end of Grady's father's fence, we need to use the midpoint formula and solve for the unknown endpoint.

The midpoint formula is given by:
[tex]\[ \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right) \][/tex]
where [tex]\((x_1, y_1)\)[/tex] is the start point, and [tex]\((x_2, y_2)\)[/tex] is the endpoint of the line segment.

Given:
- Start point [tex]\((x_1, y_1) = (8, 5)\)[/tex]
- Midpoint [tex]\((\text{mid}_x, \text{mid}_y) = (3.5, -1)\)[/tex]

To find the coordinates of the other end point [tex]\((x_2, y_2)\)[/tex], we will use the midpoint formula and solve for [tex]\(x_2\)[/tex] and [tex]\(y_2\)[/tex].

Step 1: Solve for [tex]\(x_2\)[/tex]
Using the midpoint formula for the x-coordinates:
[tex]\[ 3.5 = \frac{8 + x_2}{2} \][/tex]

Multiply both sides by 2 to isolate [tex]\(x_2\)[/tex]:
[tex]\[ 7 = 8 + x_2 \][/tex]

Subtract 8 from both sides:
[tex]\[ x_2 = 7 - 8 \][/tex]
[tex]\[ x_2 = -1 \][/tex]

Step 2: Solve for [tex]\(y_2\)[/tex]
Using the midpoint formula for the y-coordinates:
[tex]\[ -1 = \frac{5 + y_2}{2} \][/tex]

Multiply both sides by 2 to isolate [tex]\(y_2\)[/tex]:
[tex]\[ -2 = 5 + y_2 \][/tex]

Subtract 5 from both sides:
[tex]\[ y_2 = -2 - 5 \][/tex]
[tex]\[ y_2 = -7 \][/tex]

Therefore, the coordinates of the other end of the fence are [tex]\((-1, -7)\)[/tex].

The correct answer is:
[tex]\[ \boxed{(-1, -7)} \][/tex]