Finding the Area of Trapezoids by Composing a Parallelogram

This lesson teaches how to find the area of a trapezoid by composing it into a parallelogram or rectangle. It reviews the area calculation for rectangles and parallelograms, then demonstrates how to create a congruent trapezoid to form a larger shape. The lesson includes examples with regular and isosceles trapezoids, emphasizing the importance of dividing the area of the larger shape to find the trapezoid's area. Common mistakes in the process are highlighted, and the lesson concludes with a summary of the learned concepts.

What is the formula for finding the area of a parallelogram?

• Length times width

• Base times height

• Length plus width

• Base plus height

When creating a rectangle from a trapezoid, what happens to the top and bottom lines?

• They disappear

• They switch places

• They remain unchanged

• They become parallel

How do you find the area of the original trapezoid after forming a rectangle?

• Add the area of the rectangle to itself

• Multiply the area of the rectangle by 2

• Subtract the area of the rectangle from itself

• Divide the area of the rectangle by 2

What is a key characteristic of an isosceles trapezoid?

• All angles are right angles

• It has no parallel sides

• Two sides are congruent

• All sides are equal

What is a common mistake when finding the area of a trapezoid?

• Adding instead of multiplying

• Using the wrong units

• Forgetting to divide the area of the larger shape by 2

• Forgetting to multiply by the height