Math Problem Statement

What is the area of the parallelogram given its vertices?

Solution

To find the area of the parallelogram, we can use the formula:

Area=u×v\text{Area} = \left| \mathbf{u} \times \mathbf{v} \right|

where u\mathbf{u} and v\mathbf{v} are two adjacent vectors that define the parallelogram.

Step-by-Step Solution:

  1. Identify vertices: The coordinates of the parallelogram vertices are:

    • A(9,3)A(-9, -3)
    • B(5,3)B(-5, -3)
    • C(6,6)C(-6, 6)
    • D(2,6)D(-2, 6)
  2. Find vectors: We can pick two adjacent sides, for example, vectors u\mathbf{u} from AA to BB and v\mathbf{v} from AA to CC: u=BA=(5,3)(9,3)=(4,0)\mathbf{u} = B - A = (-5, -3) - (-9, -3) = (4, 0) v=CA=(6,6)(9,3)=(3,9)\mathbf{v} = C - A = (-6, 6) - (-9, -3) = (3, 9)

  3. Compute the cross product (in 2D, this is equivalent to the determinant of the matrix formed by u\mathbf{u} and v\mathbf{v}): u×v=4×90×3=36=36\left| \mathbf{u} \times \mathbf{v} \right| = \left| 4 \times 9 - 0 \times 3 \right| = \left| 36 \right| = 36

Thus, the area of the parallelogram is 36 square units.

Would you like any further clarification or details?

Follow-up Questions:

  1. How do we compute the area of a parallelogram in 3D space?
  2. What is the geometric interpretation of the cross product in vector spaces?
  3. Can you explain the determinant's role in calculating the area of a parallelogram?
  4. What would happen to the area if one of the vectors was scaled by a factor?
  5. How can we verify the parallelogram's shape on a coordinate plane?

Tip:

Always ensure the vectors you choose to calculate the area are adjacent sides, as using non-adjacent sides would lead to incorrect results.

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Math Problem Analysis

Mathematical Concepts

Geometry
Vectors
Determinants

Formulas

Area of parallelogram = |u × v| (cross product of vectors)
Cross product of two vectors in 2D

Theorems

Cross product theorem
Determinant and area in 2D space

Suitable Grade Level

Grades 9-12