Triangle
Areas of plane figures
 
Deduce the formula for the area of a triangle.
 

Drag the triangle to the horizontal line below. Then drag another equal triangle and put it inverted on its right or on its left until you form a parallelogram.

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

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

- With this information, deduce the formula for the area of the triangle. Write it down in your notebook.
       
           
  Eduardo Barbero Corral
 
Spanish Ministry of Education , Social Afairs and Sport. Year 2007
 
 

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