Hello,
So they tell us the angle PCR is 110 degrees, and we know that angle PCQ is 50, so let's set up an equation. We don't know what angle QCR is, so that'll represent "x":
50 + x = 110
From here, subtract 50 from both sides so that "x" can be by itself:
x = 60, so the angle of QCR is 60 degrees.
Hope this helps!
May
