Decomposing Polygons for Area Calculation

Walter Unob explains how to decompose polygons, like trapezoids, into simpler shapes such as rectangles and triangles. By identifying sections of the polygon and calculating the areas of these simpler shapes, one can easily determine the total area of the polygon. The process involves splitting the polygon into known shapes, calculating their areas, and summing these areas to find the total area.

What is the main purpose of decomposing polygons?

• To color them differently

• To change their shape

• To simplify the calculation of their area

• To make them look more complex

Which shape is used as an example for decomposition in the video?

• Trapezoid

• Circle

• Square

• Pentagon

What is the first step in decomposing a polygon?

• Coloring the polygon

• Identifying sections to split into simpler shapes

• Measuring the angles

• Counting the sides

What angle is the line drawn at to create two areas in the trapezoid?

• 120°

• 90°

• 45°

• 60°

How is the area of the rectangle calculated?

• Length / Width

• Length - Width

• Length + Width

• Length * Width

What is the area of the rectangle in the example?

• 45

• 36

• 54

• 63

How is the base of the triangle determined?

• By adding the longer and shorter sides

• By subtracting the shorter side from the longer side

• By multiplying the sides

• By dividing the longer side by the shorter side

What is the height of the triangle in the example?

• 3

• 6

• 12

• 9

What is the area of the triangle in the example?

• 12

• 15

• 6

• 9

What is the total area of the trapezoid after summing the areas of the rectangle and triangle?

• 81

• 72

• 63

• 54