Parallelogram area = (height × AB) or (height × DC)
Lines AC and DB are called diagonals.
Diagonals bisect each other.
Diagonals are not equal.
Diagonals do not bisect the vertex angles.
Line 'h' is perpendicular to lines AB & DC and is
called the height or altitude.
• BOTH pairs of opposite sides are equal.
AB = DC and AD = BC
• BOTH pairs of opposite angles are equal.
∠ A = ∠ C and ∠ B = ∠ D
• Adjacent angles are supplementary.
∠ A + ∠ D = ∠ D + ∠ C = ∠ C + ∠ B = ∠ B + ∠ A = 180°
• Each diagonal forms 2 congruent triangles.
Δ ADC = Δ ABC and Δ DAB = Δ DCB
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