A right isosceles triangle contains another triangle. What is the angle α? Advanced if no trigonometry is used.

Scroll down for a solution to this problem.

## Solution

The angle α is 15°.

## Poem

Shadows everywhere

Lights have a shut down

What happened to the World

Just hate

Killing

Murdering

Lights have a shut down

No proof of sun

The stars are gone

No hope

Darkness

And torture

The lights are gone

## 2 replies on “Drop shadow II”

The first picture gives a proof, that alpha = 15° by embedding the problem in a dodecagon, using an idea of Stan Fulger found at

https://gogeometry.com/school-college/4/p1358-dodecagon-regular-concurrency-diagonal-infographic-classes.htm

The second picture is to show that alph = 15° is the only solution.

Here is the “first” picture