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Triangle Area = (b ∙ h)/2 Why? Visual proof (1)

Let's define first the objects we will be working with. We say that two figures and are equidecomposable if they can be dissected into a finite number of parts, respectively congruent. This means that if we have two figures, and we are able to cut each of them such that each cut out piece is the same for both figures, then the two of them are said to be "equidecomposable". The figures that you can build using all the pieces of a Tangram game are an example of equidecomposable figures. In the app below you will discover why, given any triangle, you can calculate its area by multiplying its base by half of its height. Use the slider to dissect (cut) the triangle and obtain an equivalent parallelogram. Move the vertices A, B and C of the triangle to explore different configurations.