Math Problem Statement

In triangle PQR, PR = (6, -4) and RQ = (-1, 8). M is the midpoint of PR. Express MQ in component form.

Solution

To express the vector MQ\overrightarrow{MQ} in component form, we need to follow these steps:

Given Information:

  • PR=(64)\overrightarrow{PR} = \begin{pmatrix} 6 \\ -4 \end{pmatrix}
  • RQ=(18)\overrightarrow{RQ} = \begin{pmatrix} -1 \\ 8 \end{pmatrix}
  • MM is the midpoint of PR\overrightarrow{PR}.

Steps:

  1. Find the coordinates of MM: Since MM is the midpoint of PR\overrightarrow{PR}, we can find MM by averaging the coordinates of PP and RR. Given that we don't have the actual coordinates of PP and RR, we can use the vector components of PR\overrightarrow{PR}.

    The midpoint formula for vectors is: M=P+R2\overrightarrow{M} = \frac{\overrightarrow{P} + \overrightarrow{R}}{2}

    But since we know the vector PR=(64)\overrightarrow{PR} = \begin{pmatrix} 6 \\ -4 \end{pmatrix}, and we assume P=(0,0)P = (0, 0) for simplicity (placing PP at the origin), then MM is simply halfway between PP and RR: M=12×PR=12×(64)=(32)M = \frac{1}{2} \times \overrightarrow{PR} = \frac{1}{2} \times \begin{pmatrix} 6 \\ -4 \end{pmatrix} = \begin{pmatrix} 3 \\ -2 \end{pmatrix}

  2. Find MQ\overrightarrow{MQ}: Now we find the vector MQ\overrightarrow{MQ} by subtracting the coordinates of MM from QQ, using the given vector RQ\overrightarrow{RQ}. Since RQ=(18)\overrightarrow{RQ} = \begin{pmatrix} -1 \\ 8 \end{pmatrix}, and M=(3,2)M = (3, -2), we can find MQ\overrightarrow{MQ} as: MQ=RQRM\overrightarrow{MQ} = \overrightarrow{RQ} - \overrightarrow{RM}

    We know that RM\overrightarrow{RM} is equal to PR/2=(32)- \overrightarrow{PR} / 2 = \begin{pmatrix} -3 \\ 2 \end{pmatrix}.

    Now, MQ=RQRM=(18)(32)=(26)\overrightarrow{MQ} = \overrightarrow{RQ} - \overrightarrow{RM} = \begin{pmatrix} -1 \\ 8 \end{pmatrix} - \begin{pmatrix} -3 \\ 2 \end{pmatrix} = \begin{pmatrix} 2 \\ 6 \end{pmatrix}.

Final Answer:

MQ=(26)\overrightarrow{MQ} = \begin{pmatrix} 2 \\ 6 \end{pmatrix}

Let me know if you need further details or have any questions! Here are a few more questions to extend the understanding of this concept:

  1. How do you calculate the midpoint of a vector using components?
  2. What are the properties of midpoints in geometric figures?
  3. How do you add or subtract vectors in component form?
  4. Can the same method be used to calculate MQ\overrightarrow{MQ} if the coordinates of PP and QQ were given directly?
  5. What is the relationship between the position vectors and geometric transformations in this problem?

Tip: Always remember that finding midpoints in vector form involves averaging the coordinates of the endpoints, making it easier to calculate distances or other related vectors!

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Math Problem Analysis

Mathematical Concepts

Vectors
Midpoints
Component Form of Vectors

Formulas

Midpoint Formula: M = (P + R) / 2
Vector Subtraction: MQ = RQ - RM

Theorems

Midpoint Theorem

Suitable Grade Level

Grades 9-11