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Explore the properties of parallelograms, solve for unknown angles, and identify different types of parallelograms such as rectangles, rhombuses, and squares. Learn to apply conditions for determining if a quadrilateral is a parallelogram.
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Warm Up: • Solve for x and y in the following parallelogram. What properties of parallelograms did you use when solving? • What is the measure of CD? • What is the measure of Angle C? • What is the sum of the interior angles of a dodecagon? 1. B C (16x – 4)o 5y – 1 2y + 8 (14x + 34)o A D 2. 3. 4.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its opposite sides are congruent.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its opposite sides are congruent. • IF both pairs of opposite sides of a quadrilateral are congruent, THEN the quadrilateral is a parallelogram.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its opposite angles are congruent.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its opposite angles are congruent. • IF both pairs of opposite angles of a quadrilateral are congruent, THEN the quadrilateral is a parallelogram.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its consecutive angles are supplementary. B C xo (180 – x)o (180 – x)o xo A D
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its consecutive angles are supplementary. • IF an angle of a quadrilateral is supplementary to both of its consecutive angles, THEN the quadrilateral is a parallelogram. B C xo (180 – x)o (180 – x)o xo A D
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its diagonals bisect each other.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF a quadrilateral is a parallelogram, THEN its diagonals bisect each other. • IF the diagonals of a quadrilateral bisect each other, THEN the quadrilateral is a parallelogram.
Conditions of Parallelograms (6.3) and Special Parallelograms (6.4) • IF one pair of opposite sides of a quadrilateral are parallel AND congruent, THEN the quadrilateral is a parallelogram.
Show that ABCD is a parallelogram for m = 12 and n = 9.5; which one of the conditions of parallelograms did you use? B C (7m – 29)o (12n + 11)o (2m + 31)o A D
Are each of the given quadrilaterals also parallelograms? Justify your answer. # 1 # 2 # 3 7 7
Find x and y so the quadrilateral is a parallelogram. (x – 12)o B C (3y – 4)o (4x – 8)o A D (1/2 y)o
RECTANGLE • Four Right Angles • Congruent Diagonals • Properties of a Parallelogram
RHOMBUS • Four Congruent Sides • Perpendicular Diagonals • Diagonals Bisect Opposite • Angles • Properties of a Parallelogram
SQUARE • Properties of a Rectangle • Properties of a Rhombus
ABCD is a rhombus. Find the measure of Angle B. (y + 2)o B C (2y + 10)o A D
Show the diagonals • ofsquare ABCD • are congruent • perpendicular • bisectors of each • other. • A (-1, 0) • B (-3, 5) • C (2, 7) • D (4, 2)