A right triangle with an inscribed square. What is the area of the triangular part on the right?
Scroll down for a solution to this problem.
Solution
The area x is 6.
![](https://mirangu.com/wp-content/uploads/2021/05/AwningTentSolution.jpg)
First we deduce a general theorem by Thanos Kalogerakis relating areas x, y en z. These triangles are all similar. Name the common smallest angle α and set the square side to 1. The right-angled sides can be found as shown.
Now x=1/(2tan(α)), y=tan(α)/2 and z=sin(α)cos(α)/2. Calculate 1/x+1/y=2tan(α)+2/tan(α)=2sin(α)/cos(α)+2cos(α)/sin(α)=2/(sin(α)cos(α))=1/z. So we have the equation 1/x+1/y=1/z. Using y=3 and z=2, it follows that x=6.
Visual solution
![](https://mirangu.com/wp-content/uploads/2021/05/AwningTentDavid.jpg)
Poem
The awning tent
Stretching tightly and transparent
Used to cover thermal solar
And sometimes also in winter
Aluminium is the structure
Against cold and warm factors
Awning is like a canopy
A woven mat like a velarium
As deployed above Colosseum.
Protecting tent and aluminium
![](https://mirangu.com/wp-content/uploads/2021/05/AwningTentBella.jpg)