Math Problem Statement

M(-4, 8) is the midpoint of DE. D has coordinates (6, 1). Find the coordinates of E.

Solution

To solve this problem, let's identify the given information and the formula we need.

Given:

  • M=(4,8)M = (-4, 8) is the midpoint of line segment DEDE.
  • Point DD has coordinates (6,1)(6, 1).
  • We need to find the coordinates of point EE.

Midpoint Formula:

The midpoint MM of a line segment connecting two points D(x1,y1)D(x_1, y_1) and E(x2,y2)E(x_2, y_2) is given by: M=(x1+x22,y1+y22)M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)

Apply the Midpoint Formula:

Since M=(4,8)M = (-4, 8), D=(6,1)D = (6, 1), and E=(x2,y2)E = (x_2, y_2), we can set up equations to solve for x2x_2 and y2y_2.

  1. For the x-coordinate: 4=6+x22-4 = \frac{6 + x_2}{2}

  2. For the y-coordinate: 8=1+y228 = \frac{1 + y_2}{2}

Solve for x2x_2 and y2y_2:

  1. Solve for x2x_2: 4=6+x22-4 = \frac{6 + x_2}{2}

Multiply both sides by 2: 8=6+x2-8 = 6 + x_2

Subtract 6 from both sides: x2=86=14x_2 = -8 - 6 = -14

  1. Solve for y2y_2: 8=1+y228 = \frac{1 + y_2}{2}

Multiply both sides by 2: 16=1+y216 = 1 + y_2

Subtract 1 from both sides: y2=161=15y_2 = 16 - 1 = 15

Coordinates of EE:

The coordinates of point EE are (14,15)(-14, 15).

Would you like further details or have any questions?

Related Questions:

  1. How would the solution change if DD and MM coordinates were different?
  2. What if MM were not the midpoint but rather some other ratio between DD and EE?
  3. How can the distance formula be applied to verify the coordinates of EE?
  4. Can we find EE if only the distance between DD and EE was given instead of the midpoint?
  5. How does this method change in three-dimensional space?

Tip:

When solving for coordinates, always check your work by substituting back into the original equations to ensure they are satisfied.

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Math Problem Analysis

Mathematical Concepts

Coordinate Geometry
Midpoint

Formulas

Midpoint Formula M = ((x1 + x2)/2, (y1 + y2)/2)

Theorems

Midpoint Theorem

Suitable Grade Level

Grades 6-8