Transcript:

Okay, here's an interesting one that somebody sent me. So ABCD is a rectangle. From A, with a radius of AD, we draw a quarter circle that intersects AB at the point E. So, ADE is a quarter circle. Then, you take from E and B, you find its midpoint and you draw a semicircle. So, EFB is a semicircle. And from point A, which is the vertex of the rectangle, you draw a tangent to the semicircle, and it intersects at point F. So, AF is a tangent to the semicircle. 

Now, what is given is that the length of the tangent is 5 units. That's all we know. What is the area of the rectangle? It's pretty interesting. So if you solve it, let me know in the comments. Bye.