Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to provide the given and statement to prove.

Concepts

properties of parallelograms, congruent triangles, corresponding angles, corresponding sides

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Additional Tags

math

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Instructional Ideas

• Create collaborative groups to complete the initial proofs
• If groups need a hint, advise them of the triangles that needed to be proven congruent

Classroom Considerations

• Pupils should be comfortable with triangle congruence proofs before this lesson
• Review of properties of quadrilaterals may be necessary

Pros

• Focuses on an application of triangle congruence
• Instructional guidance is provided

Cons

• None

Common Core

HSG-CO.C.9 HSG-CO.C.10 HSG-CO.C.11