Answer:
Your dew point would be at 10.
Step-by-step explanation:
Circumference of whole circle =

360÷20=18

hence length of arc = 1/3 pi
4^2+b^2=8^2
16+b^2=64
-16. -16
b^2= 48
Sq root each side
b= sq rt 16 sq rt 3
b= 4 sq rt 3
You would add up the length of all sides to get the area.