Can you find the area of this semi-circle with just these lines?

Hi, I'm Kalie, one of the recorders on this YouTube channel. Test out your knowledge with this simple but deceiving geometry problem!

More on auxiliary lines: https://youtu.be/V_pbceIRb34 *go to 4:17!
More on determining congruent triangles, SSS: https://www.youtube.com/watch?v=oCXrtqPlbs8&t=3s&ab_channel=InquisitiveKids

Please comment, share, like, or subscribe! Thank you! Our website: https://inquisitivekids.github.io