Parallelogram on same base and between same parallels have equal area

From Karnataka Open Educational Resources

Objectives

To verify that Parallelograms on the same base and between the same parallels are equal in area

Estimated Time

40 minutes

Prerequisites/Instructions, prior preparations, if any

Knowledge about altitude, trapezium, congruent triangles, parallelogram and its area.

Materials/ Resources needed

Digital : Click here to open the file

Non-digital : Paper, pencil, ruler, compass, protractor

Process (How to do the activity)


Download this geogebra file from this link.

Procedure :

  1. Draw AB ∥ FC and AB is the base.
  2. Draw Parallelograms ABCD and ABEF are on the same base AB and between same parallels AB and FC.
  3. Identifying plane figures on the same base and between the same parallels
  4. Identify Congruent triangles i.e. Δ BCE ≅ Δ ADF and find the area of triangles
  5. Find the area of Trapezium ABED by using finding an area tool
  6. What can you say about their areas?
  7. Proving that parallelograms on the same base and between the same parallels have equal area by using following calculations

Area of the parallelogram ABCD

= Area of the Trapezium ABED + Area of the Triangle BCE

Area of the parallelogram ABEF

= Area of the Trapezium ABED + Area of the Triangle ADF

Evaluation at the end of the activity

  1. 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 ?

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