Answer:
20 degrees
Step-by-step explanation:
You had 12 the next day and the day after that you had 18
Complete the Square:
Plug your numbers in this function
You get this
That equals 
Formulas:
A= (b1+b2) /2 X h
A= (22.2+8.52) x 9.86
A=30.72x9.86
A= 302.90