Math Problem Statement

Vi have the points A(3,1) B(2,1)C(4,3) D(x,y)A\left(-3,1\right)\text{ }B\left(2,1\right)\text{, }C\left(4,3\right)\text{ }D\left(x,y\right)

ABCD is a parallelogram when AD=BC\overrightarrow{AD}=\overrightarrow{BC}

Find the points of DD

Solution

We are given that ABCD is a parallelogram, and we need to find the coordinates of point D(x,y)D(x, y) such that AD=BC\overrightarrow{AD} = \overrightarrow{BC}.

Step 1: Use the property of parallelograms

In a parallelogram, the vector AD\overrightarrow{AD} is equal to the vector BC\overrightarrow{BC}. This gives us the equation:

AD=BC\overrightarrow{AD} = \overrightarrow{BC}

Step 2: Find the vector BC\overrightarrow{BC}

The vector BC\overrightarrow{BC} is calculated as the difference between the coordinates of point CC and point BB:

BC=(CxBx,CyBy)=(42,31)=(2,2)\overrightarrow{BC} = \left( C_x - B_x, C_y - B_y \right) = \left( 4 - 2, 3 - 1 \right) = (2, 2)

Thus, BC=(2,2)\overrightarrow{BC} = (2, 2).

Step 3: Use the vector AD=BC\overrightarrow{AD} = \overrightarrow{BC}

Now, the vector AD\overrightarrow{AD} is given by:

AD=(DxAx,DyAy)\overrightarrow{AD} = \left( D_x - A_x, D_y - A_y \right)

We are told that AD=BC=(2,2)\overrightarrow{AD} = \overrightarrow{BC} = (2, 2), so:

(DxAx,DyAy)=(2,2)(D_x - A_x, D_y - A_y) = (2, 2)

Substitute the coordinates of point A(3,1)A(-3, 1):

(Dx(3),Dy1)=(2,2)(D_x - (-3), D_y - 1) = (2, 2)

This simplifies to:

(Dx+3,Dy1)=(2,2)(D_x + 3, D_y - 1) = (2, 2)

Step 4: Solve for DxD_x and DyD_y

Now, solve each component:

  1. Dx+3=2Dx=23=1D_x + 3 = 2 \Rightarrow D_x = 2 - 3 = -1
  2. Dy1=2Dy=2+1=3D_y - 1 = 2 \Rightarrow D_y = 2 + 1 = 3

Step 5: Final coordinates of point DD

Thus, the coordinates of point DD are (1,3)(-1, 3).

Final Answer:

The coordinates of point DD are (1,3)\boxed{(-1, 3)}.


Would you like further details or clarifications? Here are some related questions:

  1. What is the general condition for the vectors of a parallelogram to be equal?
  2. How do you find the area of a parallelogram given four points?
  3. How do you prove that a quadrilateral is a parallelogram using vector properties?
  4. How can you determine the midpoint of a parallelogram's diagonal?
  5. How do you find the equation of the line passing through two points, given their coordinates?

Tip: Always remember that in a parallelogram, opposite sides are parallel and equal in length, which can help simplify vector-based problems.

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Math Problem Analysis

Mathematical Concepts

Vectors
Geometry of Parallelograms
Coordinate Geometry

Formulas

\( \overrightarrow{AB} = (B_x - A_x, B_y - A_y) \)
\( \overrightarrow{BC} = (C_x - B_x, C_y - B_y) \)
\( \overrightarrow{AD} = (D_x - A_x, D_y - A_y) \)

Theorems

Properties of parallelograms (opposite sides are equal in length and direction)

Suitable Grade Level

Grades 9-12