check the picture below.
the line QS is just a flat-line and therefore it has 180° on either side, so the angle QPR is 57°, as you see there, and since we know the diameter is 20, that simply means the radius of the circle is 10.

360 - 160 - 60 = 140
<span><y = 1/2 * 140 = 70
Hope this helps
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Answer:
4.
Step-by-step explanation:
because i said so. :)