Trapezium
Areas of plane figures
 

Deduce the formula for the area of a trapezium.

Drag the trapezium to the horizontal line below. Then drag another equal trapezium and put it inverted on its right or on its left.

Check that you can form a parallelogram with two equal trapeziums.

- What is the relation between the base and the perpendicular height of the trapezium and the base and the perpendicular height of the parallelogram?

- What is the ratio of the area of a trapezium to the area of the parallelogram?

- With this information, deduce the formula for the area of the trapezium. Write it down in your notebook.


       
           
  Eduardo Barbero Corral
 
Spanish Ministry of Education , Social Afairs and Sport. Year 2007
 
 

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