Ivan Shishkin, Oaks in Old Peterhof

Equality of areas in a triangle

Reviewed

Show that the areas of the two triangles ABMABM and ACMACM, defined by a median of an arbitrary triangle ABCABC as in the following figure, are equal.

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Solutions

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Hint 1

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Solution by Ancient Tree

1 useful vote

Image2
By definition, the median of ABCABC from vertex AA splits BCBC into two segments of same length :
BM=MCBM=MC
Furthermore, the two triangles ABMABM and AMCAMC have the same height AHAH.

The area of the two triangles are respectively BM×HA2\frac{BM \times HA}{2} and MC×AH2\frac{MC\times AH}{2}, which are therefore equal.