Creation of this resource was inspired by a [url=https://twitter.com/gogeometry/status/1002274449981366277]tweet[/url] from [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url] (GoGeometry). [br][br]Both circles you see are externally tangent to each other.[br]In addition, both lines you see are externally tangent to both circles. [br][br]Note: [br]The [b]LARGE POINTS[/b] are [b]MOVEABLE[/b].

Now, here's another question: [br][br]We now know that the areas of both [b][color=#bf9000]manila triangles[/color][/b] (shown below) are equal. [br]Yet how can we prove that the area of the [b][color=#38761d]green quadrilateral[/color][/b] = double the area of one of these triangles?