An equilateral triangle inscribed in a rectangle. What is its area X in terms of triangle areas A and B?

Solution

The area X=2√(A²+AB+B²).

Poem

The cowbell in Switzerland
And this bell hanging on their neck
And flowers on their head
A wonderful sound
This aesthetically chimes
Accompagnying the transhumance of the nomadic herd
Such wonderful carillons
They clang in unisson
With the rythmic mouvements
As they walk

Bella