<span>To find the circumference, the area first needs to be found to discover the radius. Area equals (r^2) multiplied by pi, or approximately 3.14. In this case, 12.5/3.14 gives a radius^2 of 3.98 feet. The square root of 3.98 is 1.99 feet. Using the radius, the diameter and circumference can now be found. The diameter is (2r), which would also be 3.98 feet in this case. 3.98 * 3.14 gives a circumference of 12.4972 feet.</span>
So you would have -20C. Then you would multiply that by 1.8 which would give you -36 then you would add 32 which gives you your final answer which is -4 F