Hello, kapitanvicki!

A trapezium is divided into 4 triangles by its diagonals.

Prove the areas of the coloured triangles are equal.Code:B C * * * * * * * *|:::* *:::|:* *:|:::::::::*:::::::|:::::* *::|:::::* O *:|:::::::* *:::|:* | *:::::::* *::* | | *:::* *::* * * * * * * * * * * * * * A E F D

We have trapezoid with diagonals and ,

. . intersecting at

and have a common base, , and equal altitudes,

. . Hence: .

They share