# Any smart ideas on finding the area of this shaded region?

Don’t let the simplicity of this diagram fool you. I have been wondering about this for quite some time, but I can’t think of an easy/smart way of finding it.

Any ideas?

For reference, the Area is:

We observe that $\triangle PRT$ can be partitioned into five congruent sub-triangles. Therefore, the entire shaded region has area given by …
Since $\theta = \operatorname{atan}\frac{1}{2}$, this becomes