Learn on PengiReveal Math, Course 1Module 8: Area

8-3 Area of Trapezoids

In this Grade 6 lesson from Reveal Math, Course 1, students learn how to find the area of a trapezoid using three methods: decomposing it into triangles and rectangles, composing two congruent trapezoids into a parallelogram, and applying the area formula A = ½h(b₁ + b₂). The lesson builds understanding of trapezoid-specific vocabulary including base, height, and the relationship between parallel sides. Students also practice finding missing dimensions using the formula within the context of Module 8: Area.

Section 1

Definition and Parts of a Trapezoid

Property

A trapezoid is a four-sided shape (quadrilateral) with exactly one pair of parallel sides.

  • Bases (b1b_1 and b2b_2): The two parallel sides. They are usually different lengths.
  • Height (hh): The straight, perpendicular distance between the two bases.

Examples

  • A trapezoid has a top base of 6 inches and a bottom base of 10 inches. Its height is the straight 5-inch line connecting them, not the slanted sides on the edges.
  • A right trapezoid has one straight side that forms a 90° angle with the bases. In this case, that straight side is the height!

Explanation

Think of a trapezoid as a triangle that had its top chopped off perfectly straight! The most important rule is identifying the bases and the height. The bases are the two lines that will never touch, no matter how far you draw them. The height is the straight-up distance between those bases, always forming a perfect right angle.

Book overview

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Module 8: Area

  1. Lesson 1

    8-1 Area of Parallelograms

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  2. Lesson 2

    8-2 Area of Triangles

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  3. Lesson 3Current

    8-3 Area of Trapezoids

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  4. Lesson 4

    8-4 Area of Regular Polygons

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  5. Lesson 5

    8-5 Polygons on the Coordinate Plane

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Lesson overview

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Section 1

Definition and Parts of a Trapezoid

Property

A trapezoid is a four-sided shape (quadrilateral) with exactly one pair of parallel sides.

  • Bases (b1b_1 and b2b_2): The two parallel sides. They are usually different lengths.
  • Height (hh): The straight, perpendicular distance between the two bases.

Examples

  • A trapezoid has a top base of 6 inches and a bottom base of 10 inches. Its height is the straight 5-inch line connecting them, not the slanted sides on the edges.
  • A right trapezoid has one straight side that forms a 90° angle with the bases. In this case, that straight side is the height!

Explanation

Think of a trapezoid as a triangle that had its top chopped off perfectly straight! The most important rule is identifying the bases and the height. The bases are the two lines that will never touch, no matter how far you draw them. The height is the straight-up distance between those bases, always forming a perfect right angle.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Module 8: Area

  1. Lesson 1

    8-1 Area of Parallelograms

    LearnPractice
  2. Lesson 2

    8-2 Area of Triangles

    LearnPractice
  3. Lesson 3Current

    8-3 Area of Trapezoids

    LearnPractice
  4. Lesson 4

    8-4 Area of Regular Polygons

    LearnPractice
  5. Lesson 5

    8-5 Polygons on the Coordinate Plane

    LearnPractice