Answer:
-0.875
Step-by-step explanation:
10 because it makes the most sense
Here we are:
Triangle PQR is equilateral, all the angles are 60, this means that triangle PSR is an isosceles triangle. 180-90=90 90/2=45 60-45=15
B=15
Hope this helps :)
I attached a couple below pictures with all the work and a bit more information to help you understand the problem.
I hope this helps! If you have any questions, just comment them below :)