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| === Prerequisites/Instructions, prior preparations, if any === | | === Prerequisites/Instructions, prior preparations, if any === |
− | Knowledge about altitude, congruent triangles, parallelogram and its area. | + | Knowledge about altitude, trapezium, congruent triangles, parallelogram and its area. |
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| === Materials/ Resources needed === | | === Materials/ Resources needed === |
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| # Draw AB ∥ FC and AB is the base. | | # Draw AB ∥ FC and AB is the base. |
| # Draw Parallelograms ABCD and ABEF are on the same base AB and between same parallels AB and FC. | | # Draw Parallelograms ABCD and ABEF are on the same base AB and between same parallels AB and FC. |
− | | + | #Identifying plane figures on the same base and between the same parallels |
− | Δ BCE ≅ Δ ADF (By SAS Congruence Criterion) | + | #Identify Congruent triangles i.e. Δ BCE ≅ Δ ADF and find the area of triangles |
− | | + | #Find the area of Trapezium ABED by using finding an area tool |
− | ar (BCE) = ar (ADF) = =
| + | #What can you say about their areas? |
− | | + | #Proving that parallelograms on the same base and between the same parallels have equal area by using following calculations |
− | ( Areas of Congruent figures are equal )
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− | OBSERVATION / RESULT / OUTCOME :
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| Area of the parallelogram ABCD | | Area of the parallelogram ABCD |
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− | = Area of the Trapezium ABED + Area of the Triangle BCE | + | = Area of the Trapezium ABED + Area of the Triangle BCE |
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− | ar (ABCD) = ar (BCE) + ar (ABED)
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− | <nowiki>= + =</nowiki>
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| Area of the parallelogram ABEF | | Area of the parallelogram ABEF |
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| = Area of the Trapezium ABED + Area of the Triangle ADF | | = Area of the Trapezium ABED + Area of the Triangle ADF |
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− | ar (ABEF) = ar (ABED) + ar (ADF)
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− | <nowiki>= + =</nowiki>
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− | Hence the theorem is verified.
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| === Evaluation at the end of the activity === | | === Evaluation at the end of the activity === |
− | # What is the relation between the area of a triangle and area of a parallelogram, if they lie on the same base and between the same parallel lines?
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| # If one rectangle and one parallelogram lying on the same base and between the same parallel lines then what will be area of the rectangle ? | | # If one rectangle and one parallelogram lying on the same base and between the same parallel lines then what will be area of the rectangle ? |
− | # In a parallelogram ABCD, AB = 7.2 cm and altitudes corresponding to sides AB and AD are respectively 10cm and 8cm. Find AD.
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| Go back to the page - [[KVS Quadrilaterals|click here]] | | Go back to the page - [[KVS Quadrilaterals|click here]] |
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| + | [[Category:Quadrilaterals]] |