Trapezoid

1.1. Knowledge to remember

Trapezoid ABCD has:

• Bottom edge AB and bottom edge DC. Side AD and side BC.
• The bottom two sides are two parallel opposite sides.

A trapezoid has a pair of parallel opposite sides.

1.2. Solve textbook exercises on pages 91 and 92

Lesson 1 of the textbook page 91:

Which of the following figures is a trapezoid?

Solution guide:

Observing the figure, we see: figure 1, figure 2, figure 4, figure 5, figure 6 is a trapezoid

Lesson 2 Textbook page 92:

Which of the three pictures below has:

– Four sides and four angles?

– Are two pairs of opposite sides parallel?

– Only one pair of opposite sides parallel?

– There are four right angles?

Solution guide:

– Figure 1, figure 2, figure 3, each shape has 4 sides and 4 corners.

– Figure 1, figure 2, each figure has two pairs of opposite parallel sides.

– Figure 3 has only one pair of parallel opposite sides.

– Figure 1 has 4 right angles

Lesson 3 Textbook page 92:

Draw two more lines to each of the shapes below to get a trapezoid:

Solution guide:

Two lines can be added to each figure as follows:

Note: there are many ways to draw two more lines to each given figure to get a trapezoid, students choose the appropriate way.

Lesson 4 Textbook page 92:

Trapezoid ABCD has which angles are right angles? Which side is perpendicular to the two bases?

A trapezoid with one side perpendicular to the two bases is called a right trapezoid

Solution guide:

Trapezoid ABCD has angle A and angle D as right angles.

Side AD is perpendicular to the two bases.