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Theorem: The segment joining the midpoints of two sides of a triangle is parallel to the third side and half its length. A two-column proof of the theorem is shown, but the proof is incomplete. A triangle with vertices A is at 6, 8. B is at 2, 2. C is at 8, 4. Segment DE with point D on side AB and point E is on side BC Statement Reason The coordinates of point D are (4, 5) and coordinates of point E are (5, 3) Length of segment DE is Square root of 5 and length of segment AC is 2 multiplied by the square root of 5 By the distance formula Segment DE is half the length of segment AC By substitution Slope of segment DE is −2 and slope of segment AC is −2 By the slope formula Segment DE is parallel to segment AC Slopes of parallel lines are equal Which of the following completes the proof? (6 points) Select one: a. By the midpoint formula b. By definition of congruence c. Given d. By construction

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Answer:

Midpoint Formula

Step-by-step explanation:

I just took the test sorry :(

The midpoint of a segment on the coordinate plane is given by half the

sum of the coordinates of the boundaries.

  • The option that completes the proof is; a. By the midpoint formula

Reasons:

The given parameters are;

The theorem to be proven: The segment joining the midpoint of two triangle is parallel to the third side and half its length.

The coordinates of the vertex point A = (6, 8)

Coordinates of the vertex point B = (2, 2)

The coordinates of the vertex point C = (8, 4)

The point D, is the midpoint of AB and the point E is the midpoint of BC

The midpoint formula is presented as follows; [tex]\displaystyle \mathbf{\left(\frac{x_1 + x_2}{2}, \, \frac{y_1 + y_2}{2} \right)}[/tex]

Therefore, we have;

[tex]\displaystyle Midpoint \ of \ AB, \ which \ is \ point \ D = \left(\frac{6 + 2}{2} , \, \frac{8 + 2}{2} \right) = \mathbf{(4, \, 5)}[/tex]

[tex]\displaystyle Midpoint \ of \ BC, \ which \ is \ point \ E = \mathbf{\left(\frac{8 + 2}{2} , \, \frac{4 + 2}{2} \right)} = (5, \, 3)[/tex]

The distance (length) formula is; d = [tex]\sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}[/tex]

The length of segment DE = √((5 - 4)² + (3 - 5)²) = √5

The length of segment AC = √((8 - 6)² + (4 - 8)²) = 2·√5

The two column proof is presented as follows;                        

[tex]\begin{tabular}{lcl}Statement &&Reason\\1.The coord of point D are (4, 5) \& the coord of point E are (5, 3)&&1.\\The length of DE is \sqrt{5} \ \mathrm{and \ the \ length \ of \ segment \ AC \ is \ 2\cdot \sqrt{5}} &&Distance formula\\Segment DE is half the length of segment AC&&Substitution property \\Slope of DE is -2 and slope of AC is -2 &&Slope formula\\Segment DE is parallel to segment AC&&Slope of \parallel lines \ are = \end{array}[/tex]

The option that completes the proof, the reason for statement 1. is a. By the midpoint formula

Statement [tex]{}[/tex]                                                                  Reason

The coordinate of point D are (4, 5) and  [tex]{}[/tex]                 By the midpoint formula

the coordinate of point E are (5, 3)

Learn more about the midpoint formula here:

https://brainly.com/question/24580893

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