Math Problem Statement

Diberikan persegi dengan panjang sisi 1 satuan seperti berikut, tentukan luas daerah yang diarsir.

Solution

Given the problem, we need to find the area of the shaded region inside the square, which has a side length of 1 unit.

Explanation:

  1. Square Properties:

    • The square ABCDABCD has a side length of 1 unit. Therefore, the area of the square is 1×1=11 \times 1 = 1 square unit.
  2. Line Intersection:

    • The lines ACAC and BDBD intersect at the center of the square, which is point OO. Since the square has a side length of 1 unit, the coordinates of point OO are (12,12)\left( \frac{1}{2}, \frac{1}{2} \right).
  3. Triangle Analysis:

    • Point MM is the midpoint of side ABAB, so MM has coordinates (12,0)\left( \frac{1}{2}, 0 \right).
    • The shaded region is a triangle with vertices AA, OO, and MM.
  4. Area of the Shaded Triangle ΔAOM\Delta AOM:

    • The formula for the area of a triangle with vertices (x1,y1)(x_1, y_1), (x2,y2)(x_2, y_2), and (x3,y3)(x_3, y_3) is: Area=12x1(y2y3)+x2(y3y1)+x3(y1y2)\text{Area} = \frac{1}{2} \left| x_1(y_2-y_3) + x_2(y_3-y_1) + x_3(y_1-y_2) \right|
    • Substituting the coordinates of points A(0,0)A(0, 0), O(12,12)O\left(\frac{1}{2}, \frac{1}{2}\right), and M(12,0)M\left(\frac{1}{2}, 0\right): Area=120(120)+12(00)+12(012)\text{Area} = \frac{1}{2} \left| 0 \left(\frac{1}{2} - 0\right) + \frac{1}{2}(0 - 0) + \frac{1}{2}(0 - \frac{1}{2}) \right| =120+018=12×18=116= \frac{1}{2} \left| 0 + 0 - \frac{1}{8} \right| = \frac{1}{2} \times \frac{1}{8} = \frac{1}{16}

Hence, the area of the shaded region is 116\frac{1}{16} square units.

Would you like more details or have any questions?

Related Questions:

  1. How do you calculate the area of a triangle given its vertices?
  2. What is the formula for the area of a square?
  3. How do you find the midpoint of a line segment in a coordinate plane?
  4. What is the relationship between diagonals in a square?
  5. How does changing the side length of a square affect the area of shapes inside it?

Tip:

When calculating the area of a triangle using vertices, always use the absolute value to ensure you get a positive result.

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Math Problem Analysis

Mathematical Concepts

Geometry
Triangles
Coordinate Geometry
Area Calculation

Formulas

Area of a triangle = 1/2 * |x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)|

Theorems

Properties of triangles
Properties of diagonals in a square
Midpoint theorem

Suitable Grade Level

Grades 7-9