his e-lesson is designed to introduce students to quadrilaterals. ncluded in this lesson are discussions of parallelograms, rectangles, and trapezoids.
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ectangle It has all of the properties of the parallelogram 4 right angles diagonals are equal
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hombus It has all of the properties of the parallelogram 4 congruent sides diagonals bisect each other at right angles
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quare It has all of the properties of the parallelogram AND the rectangle AND the rhombus.
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he Kite Hey, it looks like a kite. It has two pairs of sides. Each pair is made up of adjacent sides that are equal in length. The angles are equal where the pairs meet. Diagonals (dashed lines) meet at a right angle, and one of the diagonal bisects (cuts equally in half) the other.
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Ready for the quiz? 1. A polygon with four sides is a a) quadrilateral b) triangle c) hexagon 2. A quadrilateral with four equal sides and four equal right angles is a a) rectangle b) square c) rhombus 3. A quadrilateral with four equal right angles and two sets of parallel opposite sides that are equal. a) rectangle b) square c) rhombus 4. A quadrilateral with two sets of parallel opposites sides that are equal. a) parallelogram b) trapezoid c) cube 5. A quadrilateral with two sides that are parallel but not equal. a) rhombus b) trapezoid c) square
am thankful to all those who have encouraged me to make this presentation and specially our Principal Ms. P.Datta for giving us the opportunity to explore creative tools for making teaching/learning more interesting.
This strategy of teaching/learning is the need of the hour.
am also thankful to the software providers for allowing me to use UnFreez and G.S.P. by the help of which I am able to make it interactive.
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In a parallelogram, both pairs of opposite sides are parallel.
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Opposite angles of a parallelogram are equal. A = C and B = D
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Both pairs of opposite sides of a parallelogram are equal. AB = CD and AD = BC
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Consecutive angles of a parallelogram are supplementary. A + B = 180 0 B + C = 180 0 C + D = 180 0 D + A = 180 0
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A B C D A B C D The diagonal of a parallelogram divides it into two congruent triangles. Fig 1 Fig 2 ABC CDA ABD CDB
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A B C D ABC CDA AB = CD (opp sides are equal) BC = AD (opp sides are equal) ABC = CDA (opp angles are equal) ABC CDA (S.A.S cong axiom)
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A B C D ABD CDB AB = CD (opp sides are equal) AD = DB (opp sides are equal) DAB = BCD (opp angles are equal) ABD CDB (S.A.S cong axiom)
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A B C D The diagonals of a parallelogram bisect each other. O AO = OC and DO = OB
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Each angle of a rectangle is a right angle. A=90 0 , B=90 0 , C=90 0 , D=90 0
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AB = CD and AD = BC Both pairs of opposite sides of a rectangle are equal.
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Diagonals of a rectangle are equal. ABCD is a rectangle in which the diagonals AC = BD.
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All sides of a rhombus are equal. AB = BC = CD =DA
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Diagonals of a rhombus bisect each other at right angles. BD AC 0 DO = OB and OC = OA